321320521 has 2 divisors, whose sum is σ = 321320522. Its totient is φ = 321320520.

The previous prime is 321320509. The next prime is 321320537. The reversal of 321320521 is 125023123.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 210250000 + 111070521 = 14500^2 + 10539^2 .

It is a cyclic number.

It is not a de Polignac number, because 321320521 - 2¹⁵ = 321287753 is a prime.

It is a super-2 number, since 2×321320521² = 206493754431422882, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (321320581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160660260 + 160660261.

It is an arithmetic number, because the mean of its divisors is an integer number (160660261).

Almost surely, 2^321320521 is an apocalyptic number.

It is an amenable number.

321320521 is a deficient number, since it is larger than the sum of its proper divisors (1).

321320521 is an equidigital number, since it uses as much as digits as its factorization.

321320521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 321320521 is about 17925.4155042498. The cubic root of 321320521 is about 684.9299454172.

Adding to 321320521 its reverse (125023123), we get a palindrome (446343644).

The spelling of 321320521 in words is "three hundred twenty-one million, three hundred twenty thousand, five hundred twenty-one".