21427235917 has 2 divisors, whose sum is σ = 21427235918. Its totient is φ = 21427235916.

The previous prime is 21427235881. The next prime is 21427235933. The reversal of 21427235917 is 71953272412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17743838436 + 3683397481 = 133206^2 + 60691^2 .

It is a cyclic number.

It is not a de Polignac number, because 21427235917 - 2²⁷ = 21293018189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21427235957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10713617958 + 10713617959.

It is an arithmetic number, because the mean of its divisors is an integer number (10713617959).

Almost surely, 2^21427235917 is an apocalyptic number.

It is an amenable number.

21427235917 is a deficient number, since it is larger than the sum of its proper divisors (1).

21427235917 is an equidigital number, since it uses as much as digits as its factorization.

21427235917 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 211680, while the sum is 43.

The spelling of 21427235917 in words is "twenty-one billion, four hundred twenty-seven million, two hundred thirty-five thousand, nine hundred seventeen".