399634560 has 320 divisors, whose sum is σ = 1539541080. Its totient is φ = 98205696.

The previous prime is 399634559. The next prime is 399634567. The reversal of 399634560 is 65436993.

It is a happy number.

399634560 is a `hidden beast` number, since 3 + 9 + 9 + 634 + 5 + 6 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 271854144 + 127780416 = 16488^2 + 11304^2 .

It is a tau number, because it is divible by the number of its divisors (320).

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

It is not an unprimeable number, because it can be changed into a prime (399634567) by changing a digit.

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 39 ways as a sum of consecutive naturals, for example, 673624 + ... + 674216.

Almost surely, 2^399634560 is an apocalyptic number.

399634560 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 399634560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (769770540).

399634560 is an abundant number, since it is smaller than the sum of its proper divisors (1139906520).

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

399634560 is a wasteful number, since it uses less digits than its factorization.

399634560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 637 (or 616 counting only the distinct ones).

The product of its (nonzero) digits is 524880, while the sum is 45.

The square root of 399634560 is about 19990.8619123839. The cubic root of 399634560 is about 736.5818492831.

The spelling of 399634560 in words is "three hundred ninety-nine million, six hundred thirty-four thousand, five hundred sixty".