165437640 has 80 divisors (see below), whose sum is σ = 556065180. Its totient is φ = 44115840.

The previous prime is 165437627. The next prime is 165437647. The reversal of 165437640 is 46734561.

It is a happy number.

165437640 is a `hidden beast` number, since 1 + 6 + 5 + 4 + 3 + 7 + 640 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 139854276 + 25583364 = 11826^2 + 5058^2 .

It is a super-2 number, since 2×165437640² = 54739225457539200, which contains 22 as substring.

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

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 165437595 and 165437604.

It is not an unprimeable number, because it can be changed into a prime (165437647) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 22291 + ... + 28770.

Almost surely, 2^165437640 is an apocalyptic number.

165437640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

165437640 is an abundant number, since it is smaller than the sum of its proper divisors (390627540).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

165437640 is a wasteful number, since it uses less digits than its factorization.

165437640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51084 (or 51071 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The square root of 165437640 is about 12862.2564116876. The cubic root of 165437640 is about 548.9651505246.

The spelling of 165437640 in words is "one hundred sixty-five million, four hundred thirty-seven thousand, six hundred forty".