164561725440 has 720 divisors, whose sum is σ = 686310124500. Its totient is φ = 37604818944.

The previous prime is 164561725397. The next prime is 164561725469. The reversal of 164561725440 is 44527165461.

164561725440 is a `hidden beast` number, since 1 + 6 + 4 + 5 + 617 + 25 + 4 + 4 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 157729711104 + 6832014336 = 397152^2 + 82656^2 .

It is a tau number, because it is divible by the number of its divisors (720).

It is a super-2 number, since 2×164561725440² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 40640536 + ... + 40644584.

Almost surely, 2^164561725440 is an apocalyptic number.

164561725440 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 164561725440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (343155062250).

164561725440 is an abundant number, since it is smaller than the sum of its proper divisors (521748399060).

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

164561725440 is an equidigital number, since it uses as much as digits as its factorization.

164561725440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4102 (or 4066 counting only the distinct ones).

The product of its (nonzero) digits is 806400, while the sum is 45.

The spelling of 164561725440 in words is "one hundred sixty-four billion, five hundred sixty-one million, seven hundred twenty-five thousand, four hundred forty".