21351436679 has 2 divisors, whose sum is σ = 21351436680. Its totient is φ = 21351436678.

The previous prime is 21351436649. The next prime is 21351436699. The reversal of 21351436679 is 97663415312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21351436679 - 2²⁸ = 21083001223 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21351436649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10675718339 + 10675718340.

It is an arithmetic number, because the mean of its divisors is an integer number (10675718340).

Almost surely, 2^21351436679 is an apocalyptic number.

21351436679 is a deficient number, since it is larger than the sum of its proper divisors (1).

21351436679 is an equidigital number, since it uses as much as digits as its factorization.

21351436679 is an evil number, because the sum of its binary digits is even.

The product of its digits is 816480, while the sum is 47.

The spelling of 21351436679 in words is "twenty-one billion, three hundred fifty-one million, four hundred thirty-six thousand, six hundred seventy-nine".