12991980505397 has 4 divisors (see below), whose sum is σ = 13237112213100. Its totient is φ = 12746848797696.

The previous prime is 12991980505393. The next prime is 12991980505429. The reversal of 12991980505397 is 79350508919921.

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 9365797208881 + 3626183296516 = 3060359^2 + 1904254^2 .

It is a cyclic number.

It is not a de Polignac number, because 12991980505397 - 2² = 12991980505393 is a prime.

It is a super-2 number, since 2×12991980505397² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12991980505393) 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, 122565853772 + ... + 122565853877.

It is an arithmetic number, because the mean of its divisors is an integer number (3309278053275).

Almost surely, 2^{12991980505397} is an apocalyptic number.

It is an amenable number.

12991980505397 is a deficient number, since it is larger than the sum of its proper divisors (245131707703).

12991980505397 is an equidigital number, since it uses as much as digits as its factorization.

12991980505397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 245131707702.

The product of its (nonzero) digits is 55112400, while the sum is 68.

The spelling of 12991980505397 in words is "twelve trillion, nine hundred ninety-one billion, nine hundred eighty million, five hundred five thousand, three hundred ninety-seven".