21257392027 has 2 divisors, whose sum is σ = 21257392028. Its totient is φ = 21257392026.

The previous prime is 21257391997. The next prime is 21257392049. The reversal of 21257392027 is 72029375212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21257392027 - 2¹⁵ = 21257359259 is a prime.

It is not a weakly prime, because it can be changed into another prime (21257392087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10628696013 + 10628696014.

It is an arithmetic number, because the mean of its divisors is an integer number (10628696014).

Almost surely, 2^21257392027 is an apocalyptic number.

21257392027 is a deficient number, since it is larger than the sum of its proper divisors (1).

21257392027 is an equidigital number, since it uses as much as digits as its factorization.

21257392027 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 105840, while the sum is 40.

The spelling of 21257392027 in words is "twenty-one billion, two hundred fifty-seven million, three hundred ninety-two thousand, twenty-seven".