391910940 has 96 divisors (see below), whose sum is σ = 1223933760. Its totient is φ = 104110848.

The previous prime is 391910881. The next prime is 391910947. The reversal of 391910940 is 49019193.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 391910895 and 391910904.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391910947) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 156982 + ... + 159458.

It is an arithmetic number, because the mean of its divisors is an integer number (12749310).

Almost surely, 2^391910940 is an apocalyptic number.

391910940 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 391910940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (611966880).

391910940 is an abundant number, since it is smaller than the sum of its proper divisors (832022820).

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

391910940 is a wasteful number, since it uses less digits than its factorization.

391910940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2788 (or 2780 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 36.

The square root of 391910940 is about 19796.7406408227. The cubic root of 391910940 is about 731.8057130164.

The spelling of 391910940 in words is "three hundred ninety-one million, nine hundred ten thousand, nine hundred forty".