21021001099979 has 2 divisors, whose sum is σ = 21021001099980. Its totient is φ = 21021001099978.

The previous prime is 21021001099937. The next prime is 21021001100123. The reversal of 21021001099979 is 97999010012012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21021001099979 - 2²⁸ = 21020732664523 is a prime.

It is not a weakly prime, because it can be changed into another prime (21021001299979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510500549989 + 10510500549990.

It is an arithmetic number, because the mean of its divisors is an integer number (10510500549990).

Almost surely, 2^{21021001099979} is an apocalyptic number.

21021001099979 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021001099979 is an equidigital number, since it uses as much as digits as its factorization.

21021001099979 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 183708, while the sum is 50.

The spelling of 21021001099979 in words is "twenty-one trillion, twenty-one billion, one million, ninety-nine thousand, nine hundred seventy-nine".