621668 has 12 divisors (see below), whose sum is σ = 1103340. Its totient is φ = 306432.

The previous prime is 621641. The next prime is 621671. The reversal of 621668 is 866126.

621668 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 252004 + 369664 = 502^2 + 608^2 .

It is a super-2 number, since 2×621668² = 772942204448, which contains 22 as substring.

It is a plaindrome in base 14.

It is a self number, because there is not a number n which added to its sum of digits gives 621668.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 773 + ... + 1356.

It is an arithmetic number, because the mean of its divisors is an integer number (91945).

2⁶²¹⁶⁶⁸ is an apocalyptic number.

It is an amenable number.

621668 is a deficient number, since it is larger than the sum of its proper divisors (481672).

621668 is a wasteful number, since it uses less digits than its factorization.

621668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2206 (or 2204 counting only the distinct ones).

The product of its digits is 3456, while the sum is 29.

The square root of 621668 is about 788.4592570323. The cubic root of 621668 is about 85.3465894662.

The spelling of 621668 in words is "six hundred twenty-one thousand, six hundred sixty-eight".