21125621124 has 96 divisors (see below), whose sum is σ = 57709232000. Its totient is φ = 6664716288.

The previous prime is 21125621113. The next prime is 21125621129. The reversal of 21125621124 is 42112652112.

It is a happy number.

21125621124 is a `hidden beast` number, since 2 + 1 + 1 + 25 + 621 + 12 + 4 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (21125621129) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2361492 + ... + 2370420.

Almost surely, 2^21125621124 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21125621124, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28854616000).

21125621124 is an abundant number, since it is smaller than the sum of its proper divisors (36583610876).

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

21125621124 is a wasteful number, since it uses less digits than its factorization.

21125621124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10114 (or 10106 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The spelling of 21125621124 in words is "twenty-one billion, one hundred twenty-five million, six hundred twenty-one thousand, one hundred twenty-four".