21130312157 has 2 divisors, whose sum is σ = 21130312158. Its totient is φ = 21130312156.

The previous prime is 21130312153. The next prime is 21130312211. The reversal of 21130312157 is 75121303112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19005655321 + 2124656836 = 137861^2 + 46094^2 .

It is a cyclic number.

It is not a de Polignac number, because 21130312157 - 2² = 21130312153 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21130312153) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565156078 + 10565156079.

It is an arithmetic number, because the mean of its divisors is an integer number (10565156079).

Almost surely, 2^21130312157 is an apocalyptic number.

It is an amenable number.

21130312157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21130312157 is an equidigital number, since it uses as much as digits as its factorization.

21130312157 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1260, while the sum is 26.

Adding to 21130312157 its reverse (75121303112), we get a palindrome (96251615269).

The spelling of 21130312157 in words is "twenty-one billion, one hundred thirty million, three hundred twelve thousand, one hundred fifty-seven".