21120023988 has 72 divisors (see below), whose sum is σ = 61044617088. Its totient is φ = 6031205568.

The previous prime is 21120023987. The next prime is 21120024067. The reversal of 21120023988 is 88932002112.

21120023988 is a `hidden beast` number, since 211 + 200 + 239 + 8 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120023987) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 496945 + ... + 537767.

It is an arithmetic number, because the mean of its divisors is an integer number (847841904).

Almost surely, 2^21120023988 is an apocalyptic number.

21120023988 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21120023988 is an abundant number, since it is smaller than the sum of its proper divisors (39924593100).

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

21120023988 is a wasteful number, since it uses less digits than its factorization.

21120023988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42893 (or 42888 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The spelling of 21120023988 in words is "twenty-one billion, one hundred twenty million, twenty-three thousand, nine hundred eighty-eight".