221204531 has 2 divisors, whose sum is σ = 221204532. Its totient is φ = 221204530.

The previous prime is 221204507. The next prime is 221204539. The reversal of 221204531 is 135402122.

221204531 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221204531 - 2¹⁴ = 221188147 is a prime.

It is a super-2 number, since 2×221204531² = 97862889069859922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (221204539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110602265 + 110602266.

It is an arithmetic number, because the mean of its divisors is an integer number (110602266).

Almost surely, 2^221204531 is an apocalyptic number.

221204531 is a deficient number, since it is larger than the sum of its proper divisors (1).

221204531 is an equidigital number, since it uses as much as digits as its factorization.

221204531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 221204531 is about 14872.9462783942. The cubic root of 221204531 is about 604.7808153491.

Adding to 221204531 its reverse (135402122), we get a palindrome (356606653).

The spelling of 221204531 in words is "two hundred twenty-one million, two hundred four thousand, five hundred thirty-one".