165215640 has 128 divisors (see below), whose sum is σ = 525657600. Its totient is φ = 41425920.

The previous prime is 165215627. The next prime is 165215641. The reversal of 165215640 is 46512561.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 165215598 and 165215607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165215641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 531085 + ... + 531395.

It is an arithmetic number, because the mean of its divisors is an integer number (4106700).

Almost surely, 2^165215640 is an apocalyptic number.

165215640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 165215640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (262828800).

165215640 is an abundant number, since it is smaller than the sum of its proper divisors (360441960).

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

165215640 is a wasteful number, since it uses less digits than its factorization.

165215640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 577 (or 573 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 165215640 is about 12853.6236135963. The cubic root of 165215640 is about 548.7194893468.

The spelling of 165215640 in words is "one hundred sixty-five million, two hundred fifteen thousand, six hundred forty".