398721408 has 32 divisors (see below), whose sum is σ = 1059104760. Its totient is φ = 132907008.

The previous prime is 398721397. The next prime is 398721457. The reversal of 398721408 is 804127893.

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×398721408² = 317957522395004928, which contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 398721408.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 518785 + ... + 519552.

Almost surely, 2^398721408 is an apocalyptic number.

It is an amenable number.

398721408 is an abundant number, since it is smaller than the sum of its proper divisors (660383352).

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

398721408 is a wasteful number, since it uses less digits than its factorization.

398721408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1038354 (or 1038342 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 42.

The square root of 398721408 is about 19968.0096153823. The cubic root of 398721408 is about 736.0203995606.

The spelling of 398721408 in words is "three hundred ninety-eight million, seven hundred twenty-one thousand, four hundred eight".