393990 has 32 divisors (see below), whose sum is σ = 988416. Its totient is φ = 100320.

The previous prime is 393989. The next prime is 393997. The reversal of 393990 is 99393.

393990 is nontrivially palindromic in base 16.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (393997) 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, 405 + ... + 975.

It is an arithmetic number, because the mean of its divisors is an integer number (30888).

2³⁹³⁹⁹⁰ is an apocalyptic number.

393990 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 393990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (494208).

393990 is an abundant number, since it is smaller than the sum of its proper divisors (594426).

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

393990 is a wasteful number, since it uses less digits than its factorization.

393990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 604.

The product of its (nonzero) digits is 6561, while the sum is 33.

The square root of 393990 is about 627.6862273461. The cubic root of 393990 is about 73.3097490735.

The spelling of 393990 in words is "three hundred ninety-three thousand, nine hundred ninety".