391244656 has 80 divisors (see below), whose sum is σ = 882086400. Its totient is φ = 166233600.

The previous prime is 391244641. The next prime is 391244669. The reversal of 391244656 is 656442193.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 263436 + ... + 264916.

It is an arithmetic number, because the mean of its divisors is an integer number (11026080).

Almost surely, 2^391244656 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 391244656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (441043200).

391244656 is an abundant number, since it is smaller than the sum of its proper divisors (490841744).

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

391244656 is a wasteful number, since it uses less digits than its factorization.

391244656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1598 (or 1592 counting only the distinct ones).

The product of its digits is 155520, while the sum is 40.

The square root of 391244656 is about 19779.9053587220. The cubic root of 391244656 is about 731.3907658392.

The spelling of 391244656 in words is "three hundred ninety-one million, two hundred forty-four thousand, six hundred fifty-six".