391664240 has 160 divisors (see below), whose sum is σ = 1066646016. Its totient is φ = 132295680.

The previous prime is 391664239. The next prime is 391664249. The reversal of 391664240 is 42466193.

It is a self number, because there is not a number n which added to its sum of digits gives 391664240.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391664249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 748619 + ... + 749141.

Almost surely, 2^391664240 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 391664240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (533323008).

391664240 is an abundant number, since it is smaller than the sum of its proper divisors (674981776).

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

391664240 is a wasteful number, since it uses less digits than its factorization.

391664240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 607 (or 601 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 35.

The square root of 391664240 is about 19790.5088363084. The cubic root of 391664240 is about 731.6521284937.

The spelling of 391664240 in words is "three hundred ninety-one million, six hundred sixty-four thousand, two hundred forty".