391090440 has 128 divisors (see below), whose sum is σ = 1337938560. Its totient is φ = 90599424.

The previous prime is 391090429. The next prime is 391090493. The reversal of 391090440 is 44090193.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 391090398 and 391090407.

It is an unprimeable number.

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, 19147 + ... + 33893.

It is an arithmetic number, because the mean of its divisors is an integer number (10452645).

Almost surely, 2^391090440 is an apocalyptic number.

391090440 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 391090440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (668969280).

391090440 is an abundant number, since it is smaller than the sum of its proper divisors (946848120).

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

391090440 is a wasteful number, since it uses less digits than its factorization.

391090440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14791 (or 14787 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 30.

The square root of 391090440 is about 19776.0066747562. The cubic root of 391090440 is about 731.2946563422.

The spelling of 391090440 in words is "three hundred ninety-one million, ninety thousand, four hundred forty".