665569949 has 8 divisors (see below), whose sum is σ = 745700448. Its totient is φ = 588710160.

The previous prime is 665569939. The next prime is 665569967. The reversal of 665569949 is 949965566.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 665569949 - 2¹² = 665565853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665569909) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 817247 + ... + 818060.

It is an arithmetic number, because the mean of its divisors is an integer number (93212556).

Almost surely, 2^665569949 is an apocalyptic number.

It is an amenable number.

665569949 is a deficient number, since it is larger than the sum of its proper divisors (80130499).

665569949 is a wasteful number, since it uses less digits than its factorization.

665569949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1635355.

The product of its digits is 15746400, while the sum is 59.

The square root of 665569949 is about 25798.6423867614. The cubic root of 665569949 is about 873.1011662481.

The spelling of 665569949 in words is "six hundred sixty-five million, five hundred sixty-nine thousand, nine hundred forty-nine".