1216972693621 has 4 divisors (see below), whose sum is σ = 1220235355372. Its totient is φ = 1213710031872.

The previous prime is 1216972693613. The next prime is 1216972693627. The reversal of 1216972693621 is 1263962796121.

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 310594436100 + 906378257521 = 557310^2 + 952039^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216972693621 - 2³ = 1216972693613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216972693627) 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, 1631330316 + ... + 1631331061.

It is an arithmetic number, because the mean of its divisors is an integer number (305058838843).

Almost surely, 2^{1216972693621} is an apocalyptic number.

It is an amenable number.

1216972693621 is a deficient number, since it is larger than the sum of its proper divisors (3262661751).

1216972693621 is an equidigital number, since it uses as much as digits as its factorization.

1216972693621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3262661750.

The product of its digits is 2939328, while the sum is 55.

The spelling of 1216972693621 in words is "one trillion, two hundred sixteen billion, nine hundred seventy-two million, six hundred ninety-three thousand, six hundred twenty-one".