21000020219979 has 16 divisors (see below), whose sum is σ = 28065133633152. Its totient is φ = 13967461162368.

The previous prime is 21000020219963. The next prime is 21000020220059. The reversal of 21000020219979 is 97991202000012.

It is not a de Polignac number, because 21000020219979 - 2⁴ = 21000020219963 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21000020219979.

It is not an unprimeable number, because it can be changed into a prime (21000020218979) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 163229092 + ... + 163357694.

It is an arithmetic number, because the mean of its divisors is an integer number (1754070852072).

Almost surely, 2^{21000020219979} is an apocalyptic number.

21000020219979 is a deficient number, since it is larger than the sum of its proper divisors (7065113413173).

21000020219979 is a wasteful number, since it uses less digits than its factorization.

21000020219979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254746.

The product of its (nonzero) digits is 40824, while the sum is 42.

The spelling of 21000020219979 in words is "twenty-one trillion, twenty million, two hundred nineteen thousand, nine hundred seventy-nine".