21758238251 has 2 divisors, whose sum is σ = 21758238252. Its totient is φ = 21758238250.

The previous prime is 21758238221. The next prime is 21758238259. The reversal of 21758238251 is 15283285712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21758238251 - 2²⁶ = 21691129387 is a prime.

It is not a weakly prime, because it can be changed into another prime (21758238259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10879119125 + 10879119126.

It is an arithmetic number, because the mean of its divisors is an integer number (10879119126).

Almost surely, 2^21758238251 is an apocalyptic number.

21758238251 is a deficient number, since it is larger than the sum of its proper divisors (1).

21758238251 is an equidigital number, since it uses as much as digits as its factorization.

21758238251 is an evil number, because the sum of its binary digits is even.

The product of its digits is 268800, while the sum is 44.

The spelling of 21758238251 in words is "twenty-one billion, seven hundred fifty-eight million, two hundred thirty-eight thousand, two hundred fifty-one".