21513521527 has 2 divisors, whose sum is σ = 21513521528. Its totient is φ = 21513521526.

The previous prime is 21513521507. The next prime is 21513521531. The reversal of 21513521527 is 72512531512.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21513521527 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21513521492 and 21513521501.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21513521507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10756760763 + 10756760764.

It is an arithmetic number, because the mean of its divisors is an integer number (10756760764).

Almost surely, 2^21513521527 is an apocalyptic number.

21513521527 is a deficient number, since it is larger than the sum of its proper divisors (1).

21513521527 is an equidigital number, since it uses as much as digits as its factorization.

21513521527 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21000, while the sum is 34.

The spelling of 21513521527 in words is "twenty-one billion, five hundred thirteen million, five hundred twenty-one thousand, five hundred twenty-seven".