391649660 has 48 divisors (see below), whose sum is σ = 893706240. Its totient is φ = 143622720.

The previous prime is 391649653. The next prime is 391649663. The reversal of 391649660 is 66946193.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391649663) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4844 + ... + 28403.

It is an arithmetic number, because the mean of its divisors is an integer number (18618880).

Almost surely, 2^391649660 is an apocalyptic number.

It is an amenable number.

391649660 is an abundant number, since it is smaller than the sum of its proper divisors (502056580).

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

391649660 is a wasteful number, since it uses less digits than its factorization.

391649660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33306 (or 33304 counting only the distinct ones).

The product of its (nonzero) digits is 209952, while the sum is 44.

The square root of 391649660 is about 19790.1404744888. The cubic root of 391649660 is about 731.6430496116.

The spelling of 391649660 in words is "three hundred ninety-one million, six hundred forty-nine thousand, six hundred sixty".