21156888960 has 320 divisors, whose sum is σ = 80002818720. Its totient is φ = 5309743104.

The previous prime is 21156888941. The next prime is 21156888983. The reversal of 21156888960 is 6988865112.

It is a happy number.

21156888960 is a `hidden beast` number, since 2 + 11 + 568 + 8 + 8 + 9 + 60 = 666.

It is a tau number, because it is divible by the number of its divisors (320).

It is a super-2 number, since 2×21156888960² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 21156888897 and 21156888906.

It is a congruent number.

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, 869277 + ... + 893283.

Almost surely, 2^21156888960 is an apocalyptic number.

21156888960 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 21156888960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40001409360).

21156888960 is an abundant number, since it is smaller than the sum of its proper divisors (58845929760).

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

21156888960 is a wasteful number, since it uses less digits than its factorization.

21156888960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24055 (or 24034 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 54.

It can be divided in two parts, 21156 and 888960, that added together give a square (910116 = 954²).

The spelling of 21156888960 in words is "twenty-one billion, one hundred fifty-six million, eight hundred eighty-eight thousand, nine hundred sixty".