621650042165 has 4 divisors (see below), whose sum is σ = 745980050604. Its totient is φ = 497320033728.

The previous prime is 621650042161. The next prime is 621650042171. The reversal of 621650042165 is 561240056126.

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 75194963089 + 546455079076 = 274217^2 + 739226^2 .

It is a cyclic number.

It is not a de Polignac number, because 621650042165 - 2² = 621650042161 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 (621650042161) 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, 62165004212 + ... + 62165004221.

It is an arithmetic number, because the mean of its divisors is an integer number (186495012651).

Almost surely, 2^621650042165 is an apocalyptic number.

It is an amenable number.

621650042165 is a deficient number, since it is larger than the sum of its proper divisors (124330008439).

621650042165 is a wasteful number, since it uses less digits than its factorization.

621650042165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124330008438.

The product of its (nonzero) digits is 86400, while the sum is 38.

The spelling of 621650042165 in words is "six hundred twenty-one billion, six hundred fifty million, forty-two thousand, one hundred sixty-five".