668623 has 2 divisors, whose sum is σ = 668624. Its totient is φ = 668622.

The previous prime is 668617. The next prime is 668671. The reversal of 668623 is 326866.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 668623 - 2⁹ = 668111 is a prime.

It is a super-2 number, since 2×668623² = 894113432258, which contains 22 as substring.

668623 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (468623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334311 + 334312.

It is an arithmetic number, because the mean of its divisors is an integer number (334312).

2⁶⁶⁸⁶²³ is an apocalyptic number.

668623 is a deficient number, since it is larger than the sum of its proper divisors (1).

668623 is an equidigital number, since it uses as much as digits as its factorization.

668623 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 31.

The square root of 668623 is about 817.6937079371. The cubic root of 668623 is about 87.4434137537.

The spelling of 668623 in words is "six hundred sixty-eight thousand, six hundred twenty-three".