21512655000 has 320 divisors, whose sum is σ = 78612336000. Its totient is φ = 5434128000.

The previous prime is 21512654957. The next prime is 21512655013. The reversal of 21512655000 is 55621512.

21512655000 is a `hidden beast` number, since 2 + 1 + 5 + 1 + 2 + 655 + 0 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 2560807 + ... + 2569193.

It is an arithmetic number, because the mean of its divisors is an integer number (245663550).

Almost surely, 2^21512655000 is an apocalyptic number.

21512655000 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 21512655000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39306168000).

21512655000 is an abundant number, since it is smaller than the sum of its proper divisors (57099681000).

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

21512655000 is a wasteful number, since it uses less digits than its factorization.

21512655000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8441 (or 8416 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

The spelling of 21512655000 in words is "twenty-one billion, five hundred twelve million, six hundred fifty-five thousand".