21512469157 has 2 divisors, whose sum is σ = 21512469158. Its totient is φ = 21512469156.

The previous prime is 21512469119. The next prime is 21512469191. The reversal of 21512469157 is 75196421512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14018796801 + 7493672356 = 118401^2 + 86566^2 .

It is a cyclic number.

It is not a de Polignac number, because 21512469157 - 2¹⁵ = 21512436389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21512469757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10756234578 + 10756234579.

It is an arithmetic number, because the mean of its divisors is an integer number (10756234579).

Almost surely, 2^21512469157 is an apocalyptic number.

It is an amenable number.

21512469157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21512469157 is an equidigital number, since it uses as much as digits as its factorization.

21512469157 is an evil number, because the sum of its binary digits is even.

The product of its digits is 151200, while the sum is 43.

The spelling of 21512469157 in words is "twenty-one billion, five hundred twelve million, four hundred sixty-nine thousand, one hundred fifty-seven".