21231252402 has 16 divisors (see below), whose sum is σ = 43044183840. Its totient is φ = 6980137632.

The previous prime is 21231252373. The next prime is 21231252407. The reversal of 21231252402 is 20425213212.

It is not an unprimeable number, because it can be changed into a prime (21231252407) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24236152 + ... + 24237027.

It is an arithmetic number, because the mean of its divisors is an integer number (2690261490).

Almost surely, 2^21231252402 is an apocalyptic number.

21231252402 is an abundant number, since it is smaller than the sum of its proper divisors (21812931438).

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

21231252402 is a wasteful number, since it uses less digits than its factorization.

21231252402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48473257.

The product of its (nonzero) digits is 1920, while the sum is 24.

Adding to 21231252402 its reverse (20425213212), we get a palindrome (41656465614).

The spelling of 21231252402 in words is "twenty-one billion, two hundred thirty-one million, two hundred fifty-two thousand, four hundred two".