398905509 has 8 divisors (see below), whose sum is σ = 533553120. Its totient is φ = 265097456.

The previous prime is 398905487. The next prime is 398905517. The reversal of 398905509 is 905509893.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 398905509 - 2⁸ = 398905253 is a prime.

It is a super-2 number, since 2×398905509² = 318251210221098162, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (398905709) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 208779 + ... + 210680.

It is an arithmetic number, because the mean of its divisors is an integer number (66694140).

Almost surely, 2^398905509 is an apocalyptic number.

It is an amenable number.

398905509 is a deficient number, since it is larger than the sum of its proper divisors (134647611).

398905509 is a wasteful number, since it uses less digits than its factorization.

398905509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419779.

The product of its (nonzero) digits is 437400, while the sum is 48.

The square root of 398905509 is about 19972.6189819963. The cubic root of 398905509 is about 736.1336626387.

The spelling of 398905509 in words is "three hundred ninety-eight million, nine hundred five thousand, five hundred nine".