621646724 has 12 divisors (see below), whose sum is σ = 1091811084. Its totient is φ = 309700704.

The previous prime is 621646721. The next prime is 621646759. The reversal of 621646724 is 427646126.

It can be written as a sum of positive squares in 2 ways, for example, as 34456900 + 587189824 = 5870^2 + 24232^2 .

It is a hoax number, since the sum of its digits (38) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (621646721) 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, 279419 + ... + 281634.

It is an arithmetic number, because the mean of its divisors is an integer number (90984257).

Almost surely, 2^621646724 is an apocalyptic number.

It is an amenable number.

621646724 is a deficient number, since it is larger than the sum of its proper divisors (470164360).

621646724 is a wasteful number, since it uses less digits than its factorization.

621646724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 561334 (or 561332 counting only the distinct ones).

The product of its digits is 96768, while the sum is 38.

The square root of 621646724 is about 24932.8442821913. The cubic root of 621646724 is about 853.4561581965.

The spelling of 621646724 in words is "six hundred twenty-one million, six hundred forty-six thousand, seven hundred twenty-four".