398165640 has 64 divisors (see below), whose sum is σ = 1197884160. Its totient is φ = 105876480.

The previous prime is 398165629. The next prime is 398165641. The reversal of 398165640 is 46561893.

It is a junction number, because it is equal to n+sod(n) for n = 398165592 and 398165601.

It is not an unprimeable number, because it can be changed into a prime (398165641) 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, 39520 + ... + 48560.

It is an arithmetic number, because the mean of its divisors is an integer number (18716940).

Almost surely, 2^398165640 is an apocalyptic number.

398165640 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

398165640 is an abundant number, since it is smaller than the sum of its proper divisors (799718520).

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

398165640 is a wasteful number, since it uses less digits than its factorization.

398165640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9422 (or 9418 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 42.

The square root of 398165640 is about 19954.0883029017. The cubic root of 398165640 is about 735.6782669483.

The spelling of 398165640 in words is "three hundred ninety-eight million, one hundred sixty-five thousand, six hundred forty".