399149640 has 128 divisors (see below), whose sum is σ = 1334880000. Its totient is φ = 106089984.

The previous prime is 399149627. The next prime is 399149651. The reversal of 399149640 is 46941993.

399149640 is a `hidden beast` number, since 39 + 91 + 496 + 40 = 666.

It is a super-2 number, since 2×399149640² = 318640870224259200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 646612 + ... + 647228.

It is an arithmetic number, because the mean of its divisors is an integer number (10428750).

Almost surely, 2^399149640 is an apocalyptic number.

399149640 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 399149640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (667440000).

399149640 is an abundant number, since it is smaller than the sum of its proper divisors (935730360).

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

399149640 is a wasteful number, since it uses less digits than its factorization.

399149640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1236 (or 1226 counting only the distinct ones).

The product of its (nonzero) digits is 209952, while the sum is 45.

The square root of 399149640 is about 19978.7296893471. The cubic root of 399149640 is about 736.2838037907.

The spelling of 399149640 in words is "three hundred ninety-nine million, one hundred forty-nine thousand, six hundred forty".