21810734251 has 2 divisors, whose sum is σ = 21810734252. Its totient is φ = 21810734250.

The previous prime is 21810734237. The next prime is 21810734269. The reversal of 21810734251 is 15243701812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21810734251 - 2⁵ = 21810734219 is a prime.

It is not a weakly prime, because it can be changed into another prime (21810734551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10905367125 + 10905367126.

It is an arithmetic number, because the mean of its divisors is an integer number (10905367126).

Almost surely, 2^21810734251 is an apocalyptic number.

21810734251 is a deficient number, since it is larger than the sum of its proper divisors (1).

21810734251 is an equidigital number, since it uses as much as digits as its factorization.

21810734251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13440, while the sum is 34.

The spelling of 21810734251 in words is "twenty-one billion, eight hundred ten million, seven hundred thirty-four thousand, two hundred fifty-one".