161620369 has 3 divisors (see below), whose sum is σ = 161633083. Its totient is φ = 161607656.

The previous prime is 161620337. The next prime is 161620421. The reversal of 161620369 is 963026161.

The square root of 161620369 is 12713.

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., 153140625 + 8479744 = 12375^2 + 2912^2 .

It is not a de Polignac number, because 161620369 - 2⁵ = 161620337 is a prime.

It is a super-2 number, since 2×161620369² = 52242287351392322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161620769) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 6357 + ... + 19069.

Almost surely, 2^161620369 is an apocalyptic number.

161620369 is the 12713-rd square number.

161620369 is the 6357-th centered octagonal number.

It is an amenable number.

161620369 is a deficient number, since it is larger than the sum of its proper divisors (12714).

161620369 is an frugal number, since it uses more digits than its factorization.

161620369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25426 (or 12713 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 34.

The cubic root of 161620369 is about 544.7100205262.

Multiplying 161620369 by its product of nonzero digits (11664), we get a square (1885139984016 = 1373004²).

The spelling of 161620369 in words is "one hundred sixty-one million, six hundred twenty thousand, three hundred sixty-nine".