21390904267 has 2 divisors, whose sum is σ = 21390904268. Its totient is φ = 21390904266.

The previous prime is 21390904253. The next prime is 21390904289. The reversal of 21390904267 is 76240909312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21390904267 - 2¹⁵ = 21390871499 is a prime.

It is not a weakly prime, because it can be changed into another prime (21390901267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10695452133 + 10695452134.

It is an arithmetic number, because the mean of its divisors is an integer number (10695452134).

Almost surely, 2^21390904267 is an apocalyptic number.

21390904267 is a deficient number, since it is larger than the sum of its proper divisors (1).

21390904267 is an equidigital number, since it uses as much as digits as its factorization.

21390904267 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 163296, while the sum is 43.

The spelling of 21390904267 in words is "twenty-one billion, three hundred ninety million, nine hundred four thousand, two hundred sixty-seven".