398397440 has 156 divisors (see below), whose sum is σ = 1114926156. Its totient is φ = 136249344.

The previous prime is 398397437. The next prime is 398397443. The reversal of 398397440 is 44793893.

It is an interprime number because it is at equal distance from previous prime (398397437) and next prime (398397443).

It can be written as a sum of positive squares in 2 ways, for example, as 205520896 + 192876544 = 14336^2 + 13888^2 .

It is not an unprimeable number, because it can be changed into a prime (398397443) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1003322 + ... + 1003718.

Almost surely, 2^398397440 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 398397440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (557463078).

398397440 is an abundant number, since it is smaller than the sum of its proper divisors (716528716).

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

398397440 is an equidigital number, since it uses as much as digits as its factorization.

398397440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440 (or 411 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 47.

The square root of 398397440 is about 19959.8957913111. The cubic root of 398397440 is about 735.8210024695.

The spelling of 398397440 in words is "three hundred ninety-eight million, three hundred ninety-seven thousand, four hundred forty".