621665613 has 24 divisors (see below), whose sum is σ = 910634400. Its totient is φ = 408632544.

The previous prime is 621665593. The next prime is 621665633. The reversal of 621665613 is 316566126.

It is an interprime number because it is at equal distance from previous prime (621665593) and next prime (621665633).

It is not a de Polignac number, because 621665613 - 2⁶ = 621665549 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621665633) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 219118 + ... + 221936.

It is an arithmetic number, because the mean of its divisors is an integer number (37943100).

Almost surely, 2^621665613 is an apocalyptic number.

It is an amenable number.

621665613 is a deficient number, since it is larger than the sum of its proper divisors (288968787).

621665613 is a wasteful number, since it uses less digits than its factorization.

621665613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3161 (or 3158 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 621665613 is about 24933.2230768507. The cubic root of 621665613 is about 853.4648023184.

The spelling of 621665613 in words is "six hundred twenty-one million, six hundred sixty-five thousand, six hundred thirteen".