396979840 has 128 divisors (see below), whose sum is σ = 998600400. Its totient is φ = 150700032.

The previous prime is 396979837. The next prime is 396979861. The reversal of 396979840 is 48979693.

It can be written as a sum of positive squares in 8 ways, for example, as 293916736 + 103063104 = 17144^2 + 10152^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1354734 + ... + 1355026.

Almost surely, 2^396979840 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 396979840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (499300200).

396979840 is an abundant number, since it is smaller than the sum of its proper divisors (601620560).

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

396979840 is a wasteful number, since it uses less digits than its factorization.

396979840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414 (or 402 counting only the distinct ones).

The product of its (nonzero) digits is 2939328, while the sum is 55.

The square root of 396979840 is about 19924.3529380505. The cubic root of 396979840 is about 734.9472188177.

The spelling of 396979840 in words is "three hundred ninety-six million, nine hundred seventy-nine thousand, eight hundred forty".