21130312331 has 4 divisors (see below), whose sum is σ = 21142205112. Its totient is φ = 21118419552.

The previous prime is 21130312297. The next prime is 21130312339. The reversal of 21130312331 is 13321303112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21130312331 - 2¹⁸ = 21130050187 is a prime.

It is a super-2 number, since 2×21130312331² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21130312339) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5943725 + ... + 5947278.

It is an arithmetic number, because the mean of its divisors is an integer number (5285551278).

Almost surely, 2^21130312331 is an apocalyptic number.

21130312331 is a deficient number, since it is larger than the sum of its proper divisors (11892781).

21130312331 is a wasteful number, since it uses less digits than its factorization.

21130312331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11892780.

The product of its (nonzero) digits is 324, while the sum is 20.

Adding to 21130312331 its reverse (13321303112), we get a palindrome (34451615443).

The spelling of 21130312331 in words is "twenty-one billion, one hundred thirty million, three hundred twelve thousand, three hundred thirty-one".