21945064507 has 2 divisors, whose sum is σ = 21945064508. Its totient is φ = 21945064506.

The previous prime is 21945064501. The next prime is 21945064523. The reversal of 21945064507 is 70546054912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21945064507 - 2²³ = 21936675899 is a prime.

It is not a weakly prime, because it can be changed into another prime (21945064501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10972532253 + 10972532254.

It is an arithmetic number, because the mean of its divisors is an integer number (10972532254).

Almost surely, 2^21945064507 is an apocalyptic number.

21945064507 is a deficient number, since it is larger than the sum of its proper divisors (1).

21945064507 is an equidigital number, since it uses as much as digits as its factorization.

21945064507 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 302400, while the sum is 43.

The spelling of 21945064507 in words is "twenty-one billion, nine hundred forty-five million, sixty-four thousand, five hundred seven".