399700644 has 144 divisors (see below), whose sum is σ = 1152144000. Its totient is φ = 107787456.

The previous prime is 399700607. The next prime is 399700657. The reversal of 399700644 is 446007993.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 399700596 and 399700605.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1485742 + ... + 1486010.

It is an arithmetic number, because the mean of its divisors is an integer number (8001000).

Almost surely, 2^399700644 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 399700644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (576072000).

399700644 is an abundant number, since it is smaller than the sum of its proper divisors (752443356).

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

399700644 is a wasteful number, since it uses less digits than its factorization.

399700644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335 (or 300 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 42.

The square root of 399700644 is about 19992.5146992568. The cubic root of 399700644 is about 736.6224477006.

The spelling of 399700644 in words is "three hundred ninety-nine million, seven hundred thousand, six hundred forty-four".