391137648 has 160 divisors (see below), whose sum is σ = 1173258240. Its totient is φ = 111041280.

The previous prime is 391137623. The next prime is 391137661. The reversal of 391137648 is 846731193.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1273911 + ... + 1274217.

It is an arithmetic number, because the mean of its divisors is an integer number (7332864).

Almost surely, 2^391137648 is an apocalyptic number.

391137648 is a gapful number since it is divisible by the number (38) 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 391137648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (586629120).

391137648 is an abundant number, since it is smaller than the sum of its proper divisors (782120592).

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

391137648 is a wasteful number, since it uses less digits than its factorization.

391137648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 475 (or 469 counting only the distinct ones).

The product of its digits is 108864, while the sum is 42.

The square root of 391137648 is about 19777.2002062982. The cubic root of 391137648 is about 731.3240796892.

The spelling of 391137648 in words is "three hundred ninety-one million, one hundred thirty-seven thousand, six hundred forty-eight".