621618866 has 12 divisors (see below), whose sum is σ = 1024900926. Its totient is φ = 282553920.

The previous prime is 621618863. The next prime is 621618869. The reversal of 621618866 is 668816126.

It is an interprime number because it is at equal distance from previous prime (621618863) and next prime (621618869).

It can be written as a sum of positive squares in only one way, i.e., 551545225 + 70073641 = 23485^2 + 8371^2 .

It is not an unprimeable number, because it can be changed into a prime (621618863) 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 5 ways as a sum of consecutive naturals, for example, 1284095 + ... + 1284578.

Almost surely, 2^621618866 is an apocalyptic number.

621618866 is a deficient number, since it is larger than the sum of its proper divisors (403282060).

621618866 is a wasteful number, since it uses less digits than its factorization.

621618866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2568697 (or 2568686 counting only the distinct ones).

The product of its digits is 165888, while the sum is 44.

The square root of 621618866 is about 24932.2856152419. The cubic root of 621618866 is about 853.4434092959.

The spelling of 621618866 in words is "six hundred twenty-one million, six hundred eighteen thousand, eight hundred sixty-six".