398635809 has 32 divisors (see below), whose sum is σ = 625895424. Its totient is φ = 222492480.

The previous prime is 398635799. The next prime is 398635813. The reversal of 398635809 is 908536893.

It is not a de Polignac number, because 398635809 - 2⁵ = 398635777 is a prime.

It is not an unprimeable number, because it can be changed into a prime (398635829) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 251032 + ... + 252614.

It is an arithmetic number, because the mean of its divisors is an integer number (19559232).

Almost surely, 2^398635809 is an apocalyptic number.

398635809 is a gapful number since it is divisible by the number (39) formed by its first and last digit.

It is an amenable number.

398635809 is a deficient number, since it is larger than the sum of its proper divisors (227259615).

398635809 is a wasteful number, since it uses less digits than its factorization.

398635809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2197.

The product of its (nonzero) digits is 1399680, while the sum is 51.

The square root of 398635809 is about 19965.8660969165. The cubic root of 398635809 is about 735.9677252555.

The spelling of 398635809 in words is "three hundred ninety-eight million, six hundred thirty-five thousand, eight hundred nine".