668402023 has 4 divisors (see below), whose sum is σ = 677816208. Its totient is φ = 658987840.

The previous prime is 668401999. The next prime is 668402029. The reversal of 668402023 is 320204866.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 668402023 - 2⁵ = 668401991 is a prime.

It is a super-2 number, since 2×668402023² = 893522528700985058, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668402029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4706986 + ... + 4707127.

It is an arithmetic number, because the mean of its divisors is an integer number (169454052).

Almost surely, 2^668402023 is an apocalyptic number.

668402023 is a deficient number, since it is larger than the sum of its proper divisors (9414185).

668402023 is an equidigital number, since it uses as much as digits as its factorization.

668402023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9414184.

The product of its (nonzero) digits is 13824, while the sum is 31.

The square root of 668402023 is about 25853.4721652624. The cubic root of 668402023 is about 874.3377946933.

Adding to 668402023 its reverse (320204866), we get a palindrome (988606889).

The spelling of 668402023 in words is "six hundred sixty-eight million, four hundred two thousand, twenty-three".