165265531640 has 128 divisors (see below), whose sum is σ = 409812073920. Its totient is φ = 59977899520.

The previous prime is 165265531609. The next prime is 165265531643. The reversal of 165265531640 is 46135562561.

It is a super-3 number, since 3×165265531640³ (a number of 35 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a junction number, because it is equal to n+sod(n) for n = 165265531591 and 165265531600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165265531643) 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, 29651894 + ... + 29657466.

Almost surely, 2^165265531640 is an apocalyptic number.

165265531640 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 165265531640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (204906036960).

165265531640 is an abundant number, since it is smaller than the sum of its proper divisors (244546542280).

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

165265531640 is a wasteful number, since it uses less digits than its factorization.

165265531640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6174 (or 6148 counting only the distinct ones).

The product of its (nonzero) digits is 648000, while the sum is 44.

The spelling of 165265531640 in words is "one hundred sixty-five billion, two hundred sixty-five million, five hundred thirty-one thousand, six hundred forty".