21104642879 has 2 divisors, whose sum is σ = 21104642880. Its totient is φ = 21104642878.

The previous prime is 21104642851. The next prime is 21104642921. The reversal of 21104642879 is 97824640112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21104642879 - 2⁸ = 21104642623 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21104642479) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10552321439 + 10552321440.

It is an arithmetic number, because the mean of its divisors is an integer number (10552321440).

Almost surely, 2^21104642879 is an apocalyptic number.

21104642879 is a deficient number, since it is larger than the sum of its proper divisors (1).

21104642879 is an equidigital number, since it uses as much as digits as its factorization.

21104642879 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 193536, while the sum is 44.

The spelling of 21104642879 in words is "twenty-one billion, one hundred four million, six hundred forty-two thousand, eight hundred seventy-nine".