398960640 has 480 divisors, whose sum is σ = 1581620040. Its totient is φ = 95551488.

The previous prime is 398960633. The next prime is 398960701. The reversal of 398960640 is 46069893.

398960640 is a `hidden beast` number, since 39 + 8 + 9 + 606 + 4 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 329204736 + 69755904 = 18144^2 + 8352^2 .

It is a tau number, because it is divible by the number of its divisors (480).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 10782702 + ... + 10782738.

Almost surely, 2^398960640 is an apocalyptic number.

398960640 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 398960640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (790810020).

398960640 is an abundant number, since it is smaller than the sum of its proper divisors (1182659400).

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

398960640 is a wasteful number, since it uses less digits than its factorization.

398960640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89 (or 60 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 45.

The square root of 398960640 is about 19973.9990988285. Note that the first 3 decimals coincide. The cubic root of 398960640 is about 736.1675736899.

The spelling of 398960640 in words is "three hundred ninety-eight million, nine hundred sixty thousand, six hundred forty".