21877948709 has 2 divisors, whose sum is σ = 21877948710. Its totient is φ = 21877948708.

The previous prime is 21877948597. The next prime is 21877948721. The reversal of 21877948709 is 90784977812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17716408609 + 4161540100 = 133103^2 + 64510^2 .

It is a cyclic number.

It is not a de Polignac number, because 21877948709 - 2²⁸ = 21609513253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21877948909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10938974354 + 10938974355.

It is an arithmetic number, because the mean of its divisors is an integer number (10938974355).

Almost surely, 2^21877948709 is an apocalyptic number.

It is an amenable number.

21877948709 is a deficient number, since it is larger than the sum of its proper divisors (1).

21877948709 is an equidigital number, since it uses as much as digits as its factorization.

21877948709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14224896, while the sum is 62.

The spelling of 21877948709 in words is "twenty-one billion, eight hundred seventy-seven million, nine hundred forty-eight thousand, seven hundred nine".