1665700969 has 3 divisors (see below), whose sum is σ = 1665741783. Its totient is φ = 1665660156.

The previous prime is 1665700931. The next prime is 1665700991. The reversal of 1665700969 is 9690075661.

The square root of 1665700969 is 40813.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 1664232025 + 1468944 = 40795^2 + 1212^2 .

It is not a de Polignac number, because 1665700969 - 2¹¹ = 1665698921 is a prime.

It is a super-2 number, since 2×1665700969² = 5549119436255077922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1665700999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 20407 + ... + 61219.

It is an arithmetic number, because the mean of its divisors is an integer number (555247261).

Almost surely, 2^1665700969 is an apocalyptic number.

1665700969 is the 40813-rd square number.

1665700969 is the 20407-th centered octagonal number.

It is an amenable number.

1665700969 is a deficient number, since it is larger than the sum of its proper divisors (40814).

1665700969 is an frugal number, since it uses more digits than its factorization.

1665700969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81626 (or 40813 counting only the distinct ones).

The product of its (nonzero) digits is 612360, while the sum is 49.

The cubic root of 1665700969 is about 1185.4020650173.

Multiplying 1665700969 by its sum of digits (49), we get a square (81619347481 = 285691²).

The spelling of 1665700969 in words is "one billion, six hundred sixty-five million, seven hundred thousand, nine hundred sixty-nine".