21212119979 has 4 divisors (see below), whose sum is σ = 21235202640. Its totient is φ = 21189037320.

The previous prime is 21212119949. The next prime is 21212119997. The reversal of 21212119979 is 97991121212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21212119979 - 2²⁰ = 21211071403 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212119949) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11539952 + ... + 11541789.

It is an arithmetic number, because the mean of its divisors is an integer number (5308800660).

Almost surely, 2^21212119979 is an apocalyptic number.

21212119979 is a deficient number, since it is larger than the sum of its proper divisors (23082661).

21212119979 is an equidigital number, since it uses as much as digits as its factorization.

21212119979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23082660.

The product of its digits is 40824, while the sum is 44.

The spelling of 21212119979 in words is "twenty-one billion, two hundred twelve million, one hundred nineteen thousand, nine hundred seventy-nine".