531390221 has 2 divisors, whose sum is σ = 531390222. Its totient is φ = 531390220.

The previous prime is 531390191. The next prime is 531390239. The reversal of 531390221 is 122093135.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 317908900 + 213481321 = 17830^2 + 14611^2 .

It is a cyclic number.

It is not a de Polignac number, because 531390221 - 2¹⁴ = 531373837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (531390121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 265695110 + 265695111.

It is an arithmetic number, because the mean of its divisors is an integer number (265695111).

Almost surely, 2^531390221 is an apocalyptic number.

It is an amenable number.

531390221 is a deficient number, since it is larger than the sum of its proper divisors (1).

531390221 is an equidigital number, since it uses as much as digits as its factorization.

531390221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1620, while the sum is 26.

The square root of 531390221 is about 23051.9027631126. The cubic root of 531390221 is about 809.9742007736.

The spelling of 531390221 in words is "five hundred thirty-one million, three hundred ninety thousand, two hundred twenty-one".