21101221209979 has 2 divisors, whose sum is σ = 21101221209980. Its totient is φ = 21101221209978.

The previous prime is 21101221209967. The next prime is 21101221210037. The reversal of 21101221209979 is 97990212210112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21101221209979 - 2⁵ = 21101221209947 is a prime.

It is a super-2 number, since 2×21101221209979² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21101221200979) 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, 10550610604989 + 10550610604990.

It is an arithmetic number, because the mean of its divisors is an integer number (10550610604990).

Almost surely, 2^{21101221209979} is an apocalyptic number.

21101221209979 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101221209979 is an equidigital number, since it uses as much as digits as its factorization.

21101221209979 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 81648, while the sum is 46.

The spelling of 21101221209979 in words is "twenty-one trillion, one hundred one billion, two hundred twenty-one million, two hundred nine thousand, nine hundred seventy-nine".