221329531 has 2 divisors, whose sum is σ = 221329532. Its totient is φ = 221329530.

The previous prime is 221329469. The next prime is 221329567. The reversal of 221329531 is 135923122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221329531 - 2⁷ = 221329403 is a prime.

It is a super-2 number, since 2×221329531² = 97973522585359922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 221329531.

It is not a weakly prime, because it can be changed into another prime (221329571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110664765 + 110664766.

It is an arithmetic number, because the mean of its divisors is an integer number (110664766).

Almost surely, 2^221329531 is an apocalyptic number.

221329531 is a deficient number, since it is larger than the sum of its proper divisors (1).

221329531 is an equidigital number, since it uses as much as digits as its factorization.

221329531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3240, while the sum is 28.

The square root of 221329531 is about 14877.1479457590. The cubic root of 221329531 is about 604.8947120013.

The spelling of 221329531 in words is "two hundred twenty-one million, three hundred twenty-nine thousand, five hundred thirty-one".