21129315679 has 2 divisors, whose sum is σ = 21129315680. Its totient is φ = 21129315678.

The previous prime is 21129315671. The next prime is 21129315721. The reversal of 21129315679 is 97651392112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21129315679 - 2³ = 21129315671 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21129315671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10564657839 + 10564657840.

It is an arithmetic number, because the mean of its divisors is an integer number (10564657840).

Almost surely, 2^21129315679 is an apocalyptic number.

21129315679 is a deficient number, since it is larger than the sum of its proper divisors (1).

21129315679 is an equidigital number, since it uses as much as digits as its factorization.

21129315679 is an evil number, because the sum of its binary digits is even.

The product of its digits is 204120, while the sum is 46.

The spelling of 21129315679 in words is "twenty-one billion, one hundred twenty-nine million, three hundred fifteen thousand, six hundred seventy-nine".