21131003121 has 32 divisors (see below), whose sum is σ = 30090547200. Its totient is φ = 13152222720.

The previous prime is 21131003099. The next prime is 21131003123. The reversal of 21131003121 is 12130013112.

It is a happy number.

It is not a de Polignac number, because 21131003121 - 2⁶ = 21131003057 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21131003121.

It is not an unprimeable number, because it can be changed into a prime (21131003123) 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, 1313436 + ... + 1329426.

It is an arithmetic number, because the mean of its divisors is an integer number (940329600).

Almost surely, 2^21131003121 is an apocalyptic number.

It is an amenable number.

21131003121 is a deficient number, since it is larger than the sum of its proper divisors (8959544079).

21131003121 is a wasteful number, since it uses less digits than its factorization.

21131003121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16349.

The product of its (nonzero) digits is 36, while the sum is 15.

Adding to 21131003121 its reverse (12130013112), we get a palindrome (33261016233).

Subtracting from 21131003121 its reverse (12130013112), we obtain a palindrome (9000990009).

The spelling of 21131003121 in words is "twenty-one billion, one hundred thirty-one million, three thousand, one hundred twenty-one".