8161585920 has 360 divisors, whose sum is σ = 29417705856. Its totient is φ = 2160525312.

The previous prime is 8161585909. The next prime is 8161585933. The reversal of 8161585920 is 295851618.

It is a happy number.

8161585920 is a `hidden beast` number, since 8 + 1 + 6 + 1 + 58 + 592 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (360).

It is a super-2 number, since 2×8161585920² (a number of 21 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 polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 23120464 + ... + 23120816.

Almost surely, 2^8161585920 is an apocalyptic number.

8161585920 is a gapful number since it is divisible by the number (80) 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 8161585920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14708852928).

8161585920 is an abundant number, since it is smaller than the sum of its proper divisors (21256119936).

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

8161585920 is a wasteful number, since it uses less digits than its factorization.

8161585920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 609 (or 586 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 45.

The square root of 8161585920 is about 90341.4961133587. The cubic root of 8161585920 is about 2013.3758373944.

The spelling of 8161585920 in words is "eight billion, one hundred sixty-one million, five hundred eighty-five thousand, nine hundred twenty".