21231202530 has 32 divisors (see below), whose sum is σ = 51239563200. Its totient is φ = 5630023232.

The previous prime is 21231202529. The next prime is 21231202567. The reversal of 21231202530 is 3520213212.

It is a junction number, because it is equal to n+sod(n) for n = 21231202497 and 21231202506.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1971465 + ... + 1982204.

It is an arithmetic number, because the mean of its divisors is an integer number (1601236350).

Almost surely, 2^21231202530 is an apocalyptic number.

21231202530 is an abundant number, since it is smaller than the sum of its proper divisors (30008360670).

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

21231202530 is a wasteful number, since it uses less digits than its factorization.

21231202530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3953858.

The product of its (nonzero) digits is 720, while the sum is 21.

Adding to 21231202530 its reverse (3520213212), we get a palindrome (24751415742).

The spelling of 21231202530 in words is "twenty-one billion, two hundred thirty-one million, two hundred two thousand, five hundred thirty".