21012221199979 has 2 divisors, whose sum is σ = 21012221199980. Its totient is φ = 21012221199978.

The previous prime is 21012221199941. The next prime is 21012221200021. The reversal of 21012221199979 is 97999112221012.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21012221199979 is a prime.

It is a super-3 number, since 3×21012221199979³ (a number of 41 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (21012221199479) 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, 10506110599989 + 10506110599990.

It is an arithmetic number, because the mean of its divisors is an integer number (10506110599990).

Almost surely, 2^{21012221199979} is an apocalyptic number.

21012221199979 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012221199979 is an equidigital number, since it uses as much as digits as its factorization.

21012221199979 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 734832, while the sum is 55.

The spelling of 21012221199979 in words is "twenty-one trillion, twelve billion, two hundred twenty-one million, one hundred ninety-nine thousand, nine hundred seventy-nine".