399171840 has 72 divisors (see below), whose sum is σ = 1274867328. Its totient is φ = 106444800.

The previous prime is 399171821. The next prime is 399171907. The reversal of 399171840 is 48171993.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 399171792 and 399171801.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48136 + ... + 55815.

Almost surely, 2^399171840 is an apocalyptic number.

399171840 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

399171840 is an abundant number, since it is smaller than the sum of its proper divisors (875695488).

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

399171840 is a wasteful number, since it uses less digits than its factorization.

399171840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103975 (or 103961 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 42.

The square root of 399171840 is about 19979.2852725016. The cubic root of 399171840 is about 736.2974538072.

The spelling of 399171840 in words is "three hundred ninety-nine million, one hundred seventy-one thousand, eight hundred forty".