621657129193 has 4 divisors (see below), whose sum is σ = 625616728900. Its totient is φ = 617697529488.

The previous prime is 621657129179. The next prime is 621657129209. The reversal of 621657129193 is 391921756126.

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 442400577424 + 179256551769 = 665132^2 + 423387^2 .

It is a cyclic number.

It is not a de Polignac number, because 621657129193 - 2⁵ = 621657129161 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 621657129193.

It is not an unprimeable number, because it can be changed into a prime (621657123193) 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, 1979799618 + ... + 1979799931.

It is an arithmetic number, because the mean of its divisors is an integer number (156404182225).

Almost surely, 2^621657129193 is an apocalyptic number.

It is an amenable number.

621657129193 is a deficient number, since it is larger than the sum of its proper divisors (3959599707).

621657129193 is a wasteful number, since it uses less digits than its factorization.

621657129193 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3959599706.

The product of its digits is 1224720, while the sum is 52.

The spelling of 621657129193 in words is "six hundred twenty-one billion, six hundred fifty-seven million, one hundred twenty-nine thousand, one hundred ninety-three".