321990 has 16 divisors (see below), whose sum is σ = 772848. Its totient is φ = 85856.

The previous prime is 321983. The next prime is 321991. The reversal of 321990 is 99123.

It is a happy number.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 321990.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 321990.

It is not an unprimeable number, because it can be changed into a prime (321991) 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, 5337 + ... + 5396.

It is an arithmetic number, because the mean of its divisors is an integer number (48303).

2³²¹⁹⁹⁰ is an apocalyptic number.

321990 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

321990 is an abundant number, since it is smaller than the sum of its proper divisors (450858).

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

321990 is a wasteful number, since it uses less digits than its factorization.

321990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10743.

The product of its (nonzero) digits is 486, while the sum is 24.

The square root of 321990 is about 567.4416269538. The cubic root of 321990 is about 68.5405304743.

The spelling of 321990 in words is "three hundred twenty-one thousand, nine hundred ninety".