21636525487 has 2 divisors, whose sum is σ = 21636525488. Its totient is φ = 21636525486.

The previous prime is 21636525461. The next prime is 21636525497. The reversal of 21636525487 is 78452563612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21636525487 - 2¹⁹ = 21636001199 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21636525487.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21636525497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10818262743 + 10818262744.

It is an arithmetic number, because the mean of its divisors is an integer number (10818262744).

Almost surely, 2^21636525487 is an apocalyptic number.

21636525487 is a deficient number, since it is larger than the sum of its proper divisors (1).

21636525487 is an equidigital number, since it uses as much as digits as its factorization.

21636525487 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2419200, while the sum is 49.

The spelling of 21636525487 in words is "twenty-one billion, six hundred thirty-six million, five hundred twenty-five thousand, four hundred eighty-seven".