621670665 has 64 divisors (see below), whose sum is σ = 1243533312. Its totient is φ = 257644800.

The previous prime is 621670661. The next prime is 621670681. The reversal of 621670665 is 566076126.

It is not a de Polignac number, because 621670665 - 2² = 621670661 is a prime.

It is not an unprimeable number, because it can be changed into a prime (621670661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 728379 + ... + 729231.

It is an arithmetic number, because the mean of its divisors is an integer number (19430208).

Almost surely, 2^621670665 is an apocalyptic number.

It is an amenable number.

621670665 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

621670665 is a wasteful number, since it uses less digits than its factorization.

621670665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1510.

The product of its (nonzero) digits is 90720, while the sum is 39.

The square root of 621670665 is about 24933.3243872533. The cubic root of 621670665 is about 853.4671142217.

The spelling of 621670665 in words is "six hundred twenty-one million, six hundred seventy thousand, six hundred sixty-five".