21130251231 has 16 divisors (see below), whose sum is σ = 28437342560. Its totient is φ = 13955604480.

The previous prime is 21130251203. The next prime is 21130251257. The reversal of 21130251231 is 13215203112.

It is not a de Polignac number, because 21130251231 - 2¹³ = 21130243039 is a prime.

It is a super-2 number, since 2×21130251231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21130251198 and 21130251207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21130253231) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 63825 + ... + 215253.

It is an arithmetic number, because the mean of its divisors is an integer number (1777333910).

Almost surely, 2^21130251231 is an apocalyptic number.

21130251231 is a deficient number, since it is larger than the sum of its proper divisors (7307091329).

21130251231 is a wasteful number, since it uses less digits than its factorization.

21130251231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151866.

The product of its (nonzero) digits is 360, while the sum is 21.

Adding to 21130251231 its reverse (13215203112), we get a palindrome (34345454343).

The spelling of 21130251231 in words is "twenty-one billion, one hundred thirty million, two hundred fifty-one thousand, two hundred thirty-one".