1221693950979 has 6 divisors (see below), whose sum is σ = 1764669040316. Its totient is φ = 814462633980.

The previous prime is 1221693950963. The next prime is 1221693951031. The reversal of 1221693950979 is 9790593961221.

1221693950979 is a `hidden beast` number, since 1 + 2 + 21 + 6 + 9 + 39 + 509 + 79 = 666.

It is not a de Polignac number, because 1221693950979 - 2⁴ = 1221693950963 is a prime.

It is a super-2 number, since 2×1221693950979² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221693951979) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 67871886157 + ... + 67871886174.

Almost surely, 2^{1221693950979} is an apocalyptic number.

1221693950979 is a deficient number, since it is larger than the sum of its proper divisors (542975089337).

1221693950979 is a wasteful number, since it uses less digits than its factorization.

1221693950979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135743772337 (or 135743772334 counting only the distinct ones).

The product of its (nonzero) digits is 16533720, while the sum is 63.

The spelling of 1221693950979 in words is "one trillion, two hundred twenty-one billion, six hundred ninety-three million, nine hundred fifty thousand, nine hundred seventy-nine".