621616657 has 8 divisors (see below), whose sum is σ = 632751912. Its totient is φ = 610512000.

The previous prime is 621616649. The next prime is 621616663. The reversal of 621616657 is 756616126.

It can be written as a sum of positive squares in 4 ways, for example, as 14930496 + 606686161 = 3864^2 + 24631^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 621616657 - 2³ = 621616649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (621616627) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35493 + ... + 50029.

It is an arithmetic number, because the mean of its divisors is an integer number (79093989).

Almost surely, 2^621616657 is an apocalyptic number.

It is an amenable number.

621616657 is a deficient number, since it is larger than the sum of its proper divisors (11135255).

621616657 is a wasteful number, since it uses less digits than its factorization.

621616657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15299.

The product of its digits is 90720, while the sum is 40.

The square root of 621616657 is about 24932.2413152127. The cubic root of 621616657 is about 853.4423983556.

The spelling of 621616657 in words is "six hundred twenty-one million, six hundred sixteen thousand, six hundred fifty-seven".