21031315157 has 2 divisors, whose sum is σ = 21031315158. Its totient is φ = 21031315156.

The previous prime is 21031315153. The next prime is 21031315181. The reversal of 21031315157 is 75151313012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20573312356 + 458002801 = 143434^2 + 21401^2 .

It is a cyclic number.

It is not a de Polignac number, because 21031315157 - 2² = 21031315153 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21031315153) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10515657578 + 10515657579.

It is an arithmetic number, because the mean of its divisors is an integer number (10515657579).

Almost surely, 2^21031315157 is an apocalyptic number.

It is an amenable number.

21031315157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21031315157 is an equidigital number, since it uses as much as digits as its factorization.

21031315157 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3150, while the sum is 29.

Adding to 21031315157 its reverse (75151313012), we get a palindrome (96182628169).

The spelling of 21031315157 in words is "twenty-one billion, thirty-one million, three hundred fifteen thousand, one hundred fifty-seven".