21531251432100 has 36 divisors (see below), whose sum is σ = 62297087477744. Its totient is φ = 5741667048480.

The previous prime is 21531251432081. The next prime is 21531251432101. The reversal of 21531251432100 is 123415213512.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (21531251432101) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35885418754 + ... + 35885419353.

Almost surely, 2^{21531251432100} is an apocalyptic number.

21531251432100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21531251432100 is an abundant number, since it is smaller than the sum of its proper divisors (40765836045644).

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

21531251432100 is a wasteful number, since it uses less digits than its factorization.

21531251432100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71770838124 (or 71770838117 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 30.

Adding to 21531251432100 its reverse (123415213512), we get a palindrome (21654666645612).

The spelling of 21531251432100 in words is "twenty-one trillion, five hundred thirty-one billion, two hundred fifty-one million, four hundred thirty-two thousand, one hundred".