1221693950977 has 4 divisors (see below), whose sum is σ = 1226447624196. Its totient is φ = 1216940277760.

The previous prime is 1221693950963. The next prime is 1221693951031. The reversal of 1221693950977 is 7790593961221.

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

It can be written as a sum of positive squares in 2 ways, for example, as 725501911696 + 496192039281 = 851764^2 + 704409^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221693950977 is a prime.

It is a super-2 number, since 2×1221693950977² (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 (1221693950957) 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, 2376836224 + ... + 2376836737.

It is an arithmetic number, because the mean of its divisors is an integer number (306611906049).

Almost surely, 2^{1221693950977} is an apocalyptic number.

It is an amenable number.

1221693950977 is a deficient number, since it is larger than the sum of its proper divisors (4753673219).

1221693950977 is an equidigital number, since it uses as much as digits as its factorization.

1221693950977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4753673218.

The product of its (nonzero) digits is 12859560, while the sum is 61.

The spelling of 1221693950977 in words is "one trillion, two hundred twenty-one billion, six hundred ninety-three million, nine hundred fifty thousand, nine hundred seventy-seven".