21575687212787 has 2 divisors, whose sum is σ = 21575687212788. Its totient is φ = 21575687212786.

The previous prime is 21575687212537. The next prime is 21575687212889. The reversal of 21575687212787 is 78721278657512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21575687212787 - 2²⁰ = 21575686164211 is a prime.

It is not a weakly prime, because it can be changed into another prime (21575687212187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10787843606393 + 10787843606394.

It is an arithmetic number, because the mean of its divisors is an integer number (10787843606394).

Almost surely, 2^{21575687212787} is an apocalyptic number.

21575687212787 is a deficient number, since it is larger than the sum of its proper divisors (1).

21575687212787 is an equidigital number, since it uses as much as digits as its factorization.

21575687212787 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 184396800, while the sum is 68.

The spelling of 21575687212787 in words is "twenty-one trillion, five hundred seventy-five billion, six hundred eighty-seven million, two hundred twelve thousand, seven hundred eighty-seven".