21165500160 has 216 divisors, whose sum is σ = 83692234080. Its totient is φ = 4837810176.

The previous prime is 21165500137. The next prime is 21165500173. The reversal of 21165500160 is 6100556112.

It is a happy number.

21165500160 is a `hidden beast` number, since 2 + 1 + 1 + 655 + 0 + 0 + 1 + 6 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 50595 + ... + 211874.

Almost surely, 2^21165500160 is an apocalyptic number.

21165500160 is a gapful number since it is divisible by the number (20) 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 21165500160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41846117040).

21165500160 is an abundant number, since it is smaller than the sum of its proper divisors (62526733920).

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

21165500160 is a wasteful number, since it uses less digits than its factorization.

21165500160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 262503 (or 262486 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The spelling of 21165500160 in words is "twenty-one billion, one hundred sixty-five million, five hundred thousand, one hundred sixty".