621939645 has 48 divisors (see below), whose sum is σ = 1144231920. Its totient is φ = 311427072.

The previous prime is 621939613. The next prime is 621939649. The reversal of 621939645 is 546939126.

621939645 is a `hidden beast` number, since 6 + 219 + 396 + 45 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 5212089 + 616727556 = 2283^2 + 24834^2 .

It is not a de Polignac number, because 621939645 - 2⁵ = 621939613 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 621939645.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621939649) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 440701 + ... + 442109.

It is an arithmetic number, because the mean of its divisors is an integer number (23838165).

Almost surely, 2^621939645 is an apocalyptic number.

It is an amenable number.

621939645 is a deficient number, since it is larger than the sum of its proper divisors (522292275).

621939645 is a wasteful number, since it uses less digits than its factorization.

621939645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2014 (or 2011 counting only the distinct ones).

The product of its digits is 349920, while the sum is 45.

The square root of 621939645 is about 24938.7177898143. The cubic root of 621939645 is about 853.5901871478.

The spelling of 621939645 in words is "six hundred twenty-one million, nine hundred thirty-nine thousand, six hundred forty-five".