21939130507457 has 2 divisors, whose sum is σ = 21939130507458. Its totient is φ = 21939130507456.

The previous prime is 21939130507439. The next prime is 21939130507493. The reversal of 21939130507457 is 75470503193912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13187763198016 + 8751367309441 = 3631496^2 + 2958271^2 .

It is a cyclic number.

It is not a de Polignac number, because 21939130507457 - 2⁴² = 17541083996353 is a prime.

It is not a weakly prime, because it can be changed into another prime (21939130506457) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10969565253728 + 10969565253729.

It is an arithmetic number, because the mean of its divisors is an integer number (10969565253729).

Almost surely, 2^{21939130507457} is an apocalyptic number.

It is an amenable number.

21939130507457 is a deficient number, since it is larger than the sum of its proper divisors (1).

21939130507457 is an equidigital number, since it uses as much as digits as its factorization.

21939130507457 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7144200, while the sum is 56.

The spelling of 21939130507457 in words is "twenty-one trillion, nine hundred thirty-nine billion, one hundred thirty million, five hundred seven thousand, four hundred fifty-seven".