668940 has 24 divisors (see below), whose sum is σ = 1873200. Its totient is φ = 178368.

The previous prime is 668939. The next prime is 668947. The reversal of 668940 is 49866.

It is an Ulam number.

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (668947) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5515 + ... + 5634.

It is an arithmetic number, because the mean of its divisors is an integer number (78050).

2⁶⁶⁸⁹⁴⁰ is an apocalyptic number.

668940 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

668940 is an abundant number, since it is smaller than the sum of its proper divisors (1204260).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

668940 is a wasteful number, since it uses less digits than its factorization.

668940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11161 (or 11159 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 668940 is about 817.8875228294. The cubic root of 668940 is about 87.4572307989.

The spelling of 668940 in words is "six hundred sixty-eight thousand, nine hundred forty".