165664431 has 12 divisors (see below), whose sum is σ = 242177208. Its totient is φ = 109111824.

The previous prime is 165664427. The next prime is 165664451. The reversal of 165664431 is 134466561.

It is a happy number.

165664431 is a `hidden beast` number, since 1 + 6 + 5 + 6 + 644 + 3 + 1 = 666.

It is not a de Polignac number, because 165664431 - 2² = 165664427 is a prime.

It is a super-2 number, since 2×165664431² = 54889407397107522, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165664451) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 110140 + ... + 111633.

It is an arithmetic number, because the mean of its divisors is an integer number (20181434).

Almost surely, 2^165664431 is an apocalyptic number.

165664431 is a deficient number, since it is larger than the sum of its proper divisors (76512777).

165664431 is a wasteful number, since it uses less digits than its factorization.

165664431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221862 (or 221859 counting only the distinct ones).

The product of its digits is 51840, while the sum is 36.

The square root of 165664431 is about 12871.0695359787. The cubic root of 165664431 is about 549.2158865080.

The spelling of 165664431 in words is "one hundred sixty-five million, six hundred sixty-four thousand, four hundred thirty-one".