165398640 has 320 divisors, whose sum is σ = 603389952. Its totient is φ = 37094400.

The previous prime is 165398599. The next prime is 165398647. The reversal of 165398640 is 46893561.

165398640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×165398640² = 54713420227699200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 165398592 and 165398601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165398647) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3519097 + ... + 3519143.

Almost surely, 2^165398640 is an apocalyptic number.

165398640 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 165398640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (301694976).

165398640 is an abundant number, since it is smaller than the sum of its proper divisors (437991312).

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

165398640 is a wasteful number, since it uses less digits than its factorization.

165398640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148 (or 142 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 42.

The square root of 165398640 is about 12860.7402586321. The cubic root of 165398640 is about 548.9220097507.

The spelling of 165398640 in words is "one hundred sixty-five million, three hundred ninety-eight thousand, six hundred forty".