321090561 has 45 divisors (see below), whose sum is σ = 530151699. Its totient is φ = 193525200.

The previous prime is 321090559. The next prime is 321090569. The reversal of 321090561 is 165090123.

The square root of 321090561 is 17919.

It is a perfect power (a square), and thus also a powerful number.

321090561 is a `hidden beast` number, since 3 + 2 + 10 + 90 + 561 = 666.

It can be written as a sum of positive squares in only one way, i.e., 3538161 + 317552400 = 1881^2 + 17820^2 .

It is not a de Polignac number, because 321090561 - 2¹ = 321090559 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (321090569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 1773891 + ... + 1774071.

Almost surely, 2^321090561 is an apocalyptic number.

321090561 is the 17919-th square number.

321090561 is the 8960-th centered octagonal number.

It is an amenable number.

321090561 is a deficient number, since it is larger than the sum of its proper divisors (209061138).

321090561 is an equidigital number, since it uses as much as digits as its factorization.

321090561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396 (or 195 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The cubic root of 321090561 is about 684.7665114323.

The spelling of 321090561 in words is "three hundred twenty-one million, ninety thousand, five hundred sixty-one".