646940 has 24 divisors (see below), whose sum is σ = 1552992. Its totient is φ = 221760.

The previous prime is 646937. The next prime is 646957. The reversal of 646940 is 49646.

646940 = 301² + 302² + ... + 307².

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2171 + ... + 2450.

It is an arithmetic number, because the mean of its divisors is an integer number (64708).

2⁶⁴⁶⁹⁴⁰ is an apocalyptic number.

It is an amenable number.

646940 is an abundant number, since it is smaller than the sum of its proper divisors (906052).

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

646940 is a wasteful number, since it uses less digits than its factorization.

646940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4637 (or 4635 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 646940 is about 804.3258046339. The cubic root of 646940 is about 86.4877637586.

The spelling of 646940 in words is "six hundred forty-six thousand, nine hundred forty".