390432640 has 128 divisors (see below), whose sum is σ = 1014793920. Its totient is φ = 142786560.

The previous prime is 390432629. The next prime is 390432649. The reversal of 390432640 is 46234093.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (390432649) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1389300 + ... + 1389580.

Almost surely, 2^390432640 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 390432640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (507396960).

390432640 is an abundant number, since it is smaller than the sum of its proper divisors (624361280).

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

390432640 is a wasteful number, since it uses less digits than its factorization.

390432640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 480 (or 468 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 31.

The square root of 390432640 is about 19759.3684109589. The cubic root of 390432640 is about 730.8844225203.

The spelling of 390432640 in words is "three hundred ninety million, four hundred thirty-two thousand, six hundred forty".