165391840 has 48 divisors (see below), whose sum is σ = 391583808. Its totient is φ = 66013696.

The previous prime is 165391757. The next prime is 165391847. The reversal of 165391840 is 48193561.

It is a self number, because there is not a number n which added to its sum of digits gives 165391840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165391847) 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, 103689 + ... + 105271.

It is an arithmetic number, because the mean of its divisors is an integer number (8157996).

Almost surely, 2^165391840 is an apocalyptic number.

165391840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

165391840 is an abundant number, since it is smaller than the sum of its proper divisors (226191968).

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

165391840 is a wasteful number, since it uses less digits than its factorization.

165391840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2251 (or 2243 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 37.

The square root of 165391840 is about 12860.4758854406. The cubic root of 165391840 is about 548.9144870754.

The spelling of 165391840 in words is "one hundred sixty-five million, three hundred ninety-one thousand, eight hundred forty".