398491918 has 32 divisors (see below), whose sum is σ = 674915328. Its totient is φ = 174820800.

The previous prime is 398491909. The next prime is 398491931. The reversal of 398491918 is 819194893.

It is a super-2 number, since 2×398491918² = 317591617422637448, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 420321 + ... + 421267.

It is an arithmetic number, because the mean of its divisors is an integer number (21091104).

Almost surely, 2^398491918 is an apocalyptic number.

398491918 is a deficient number, since it is larger than the sum of its proper divisors (276423410).

398491918 is a wasteful number, since it uses less digits than its factorization.

398491918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1608.

The product of its digits is 559872, while the sum is 52.

The square root of 398491918 is about 19962.2623467382. The cubic root of 398491918 is about 735.8791633202.

The spelling of 398491918 in words is "three hundred ninety-eight million, four hundred ninety-one thousand, nine hundred eighteen".