21431100402 has 24 divisors (see below), whose sum is σ = 48452923584. Its totient is φ = 6833104344.

The previous prime is 21431100401. The next prime is 21431100419. The reversal of 21431100402 is 20400113412.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21431100401) 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, 25882558 + ... + 25883385.

It is an arithmetic number, because the mean of its divisors is an integer number (2018871816).

Almost surely, 2^21431100402 is an apocalyptic number.

21431100402 is an abundant number, since it is smaller than the sum of its proper divisors (27021823182).

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

21431100402 is a wasteful number, since it uses less digits than its factorization.

21431100402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51765974 (or 51765971 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21431100402 its reverse (20400113412), we get a palindrome (41831213814).

The spelling of 21431100402 in words is "twenty-one billion, four hundred thirty-one million, one hundred thousand, four hundred two".