165939837840 has 640 divisors, whose sum is σ = 664350336000. Its totient is φ = 37288525824.

The previous prime is 165939837839. The next prime is 165939837841. The reversal of 165939837840 is 48738939561.

165939837840 is a `hidden beast` number, since 1 + 6 + 593 + 9 + 8 + 37 + 8 + 4 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (165939837839) and next prime (165939837841).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (165939837841) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 426580366 + ... + 426580754.

It is an arithmetic number, because the mean of its divisors is an integer number (1038047400).

Almost surely, 2^165939837840 is an apocalyptic number.

165939837840 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 165939837840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (332175168000).

165939837840 is an abundant number, since it is smaller than the sum of its proper divisors (498410498160).

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

165939837840 is a wasteful number, since it uses less digits than its factorization.

165939837840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 824 (or 812 counting only the distinct ones).

The product of its (nonzero) digits is 39191040, while the sum is 63.

The spelling of 165939837840 in words is "one hundred sixty-five billion, nine hundred thirty-nine million, eight hundred thirty-seven thousand, eight hundred forty".