391561488 has 90 divisors (see below), whose sum is σ = 1116625146. Its totient is φ = 128065536.

The previous prime is 391561487. The next prime is 391561517. The reversal of 391561488 is 884165193.

391561488 is a `hidden beast` number, since 3 + 9 + 1 + 561 + 4 + 88 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 9437184 + 382124304 = 3072^2 + 19548^2 .

It is not an unprimeable number, because it can be changed into a prime (391561487) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 2028720 + ... + 2028912.

Almost surely, 2^391561488 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 391561488, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (558312573).

391561488 is an abundant number, since it is smaller than the sum of its proper divisors (725063658).

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

391561488 is a wasteful number, since it uses less digits than its factorization.

391561488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 473 (or 271 counting only the distinct ones).

The product of its digits is 207360, while the sum is 45.

The square root of 391561488 is about 19787.9126741554. The cubic root of 391561488 is about 731.5881406124.

The spelling of 391561488 in words is "three hundred ninety-one million, five hundred sixty-one thousand, four hundred eighty-eight".