321981 has 12 divisors (see below), whose sum is σ = 472416. Its totient is φ = 194920.

The previous prime is 321961. The next prime is 321983. The reversal of 321981 is 189123.

It is not a de Polignac number, because 321981 - 2⁵ = 321949 is a prime.

It is a super-2 number, since 2×321981² = 207343528722, which contains 22 as substring.

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 321981.

It is not an unprimeable number, because it can be changed into a prime (321983) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 81 + ... + 806.

It is an arithmetic number, because the mean of its divisors is an integer number (39368).

2³²¹⁹⁸¹ is an apocalyptic number.

It is an amenable number.

321981 is a deficient number, since it is larger than the sum of its proper divisors (150435).

321981 is a wasteful number, since it uses less digits than its factorization.

321981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 912 (or 901 counting only the distinct ones).

The product of its digits is 432, while the sum is 24.

The square root of 321981 is about 567.4336965673. The cubic root of 321981 is about 68.5398918722.

The spelling of 321981 in words is "three hundred twenty-one thousand, nine hundred eighty-one".