391680 has 120 divisors (see below), whose sum is σ = 1436292. Its totient is φ = 98304.

The previous prime is 391679. The next prime is 391691. The reversal of 391680 is 86193.

It can be written as a sum of positive squares in 2 ways, for example, as 389376 + 2304 = 624^2 + 48^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a zygodrome in base 4.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 23032 + ... + 23048.

2³⁹¹⁶⁸⁰ is an apocalyptic number.

391680 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 391680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (718146).

391680 is an abundant number, since it is smaller than the sum of its proper divisors (1044612).

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

391680 is a wasteful number, since it uses less digits than its factorization.

391680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46 (or 27 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 391680 is about 625.8434308995. The cubic root of 391680 is about 73.1661941902.

The spelling of 391680 in words is "three hundred ninety-one thousand, six hundred eighty".