393991000 has 64 divisors (see below), whose sum is σ = 992890080. Its totient is φ = 145468800.

The previous prime is 393990991. The next prime is 393991007. The reversal of 393991000 is 199393.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (393991007) 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, 2154 + ... + 28153.

Almost surely, 2^393991000 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 393991000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (496445040).

393991000 is an abundant number, since it is smaller than the sum of its proper divisors (598899080).

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

393991000 is a wasteful number, since it uses less digits than its factorization.

393991000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30341 (or 30327 counting only the distinct ones).

The product of its (nonzero) digits is 6561, while the sum is 34.

The square root of 393991000 is about 19849.2065332597. The cubic root of 393991000 is about 733.0981109682.

The spelling of 393991000 in words is "three hundred ninety-three million, nine hundred ninety-one thousand".