391261040 has 80 divisors (see below), whose sum is σ = 948689280. Its totient is φ = 149882880.

The previous prime is 391261033. The next prime is 391261063. The reversal of 391261040 is 40162193.

It is a tau number, because it is divible by the number of its divisors (80).

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, 317225 + ... + 318455.

It is an arithmetic number, because the mean of its divisors is an integer number (11858616).

Almost surely, 2^391261040 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 391261040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (474344640).

391261040 is an abundant number, since it is smaller than the sum of its proper divisors (557428240).

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

391261040 is a wasteful number, since it uses less digits than its factorization.

391261040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1410 (or 1404 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 391261040 is about 19780.3195120807. The cubic root of 391261040 is about 731.4009750854.

The spelling of 391261040 in words is "three hundred ninety-one million, two hundred sixty-one thousand, forty".