21323121979 has 2 divisors, whose sum is σ = 21323121980. Its totient is φ = 21323121978.

The previous prime is 21323121961. The next prime is 21323122013. The reversal of 21323121979 is 97912132312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21323121979 - 2⁹ = 21323121467 is a prime.

It is not a weakly prime, because it can be changed into another prime (21323121929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10661560989 + 10661560990.

It is an arithmetic number, because the mean of its divisors is an integer number (10661560990).

Almost surely, 2^21323121979 is an apocalyptic number.

21323121979 is a deficient number, since it is larger than the sum of its proper divisors (1).

21323121979 is an equidigital number, since it uses as much as digits as its factorization.

21323121979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40824, while the sum is 40.

The spelling of 21323121979 in words is "twenty-one billion, three hundred twenty-three million, one hundred twenty-one thousand, nine hundred seventy-nine".