391999998 has 32 divisors (see below), whose sum is σ = 846720000. Its totient is φ = 120270816.

The previous prime is 391999987. The next prime is 392000009. The reversal of 391999998 is 899999193.

It is an interprime number because it is at equal distance from previous prime (391999987) and next prime (392000009).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21003 + ... + 35001.

It is an arithmetic number, because the mean of its divisors is an integer number (26460000).

Almost surely, 2^391999998 is an apocalyptic number.

391999998 is an abundant number, since it is smaller than the sum of its proper divisors (454720002).

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

391999998 is a wasteful number, since it uses less digits than its factorization.

391999998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14376.

The product of its digits is 12754584, while the sum is 66.

The square root of 391999998 is about 19798.9898227157. The cubic root of 391999998 is about 731.8611407599.

The spelling of 391999998 in words is "three hundred ninety-one million, nine hundred ninety-nine thousand, nine hundred ninety-eight".