23231531221 has 2 divisors, whose sum is σ = 23231531222. Its totient is φ = 23231531220.

The previous prime is 23231531209. The next prime is 23231531243. The reversal of 23231531221 is 12213513232.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20349022500 + 2882508721 = 142650^2 + 53689^2 .

It is a cyclic number.

It is not a de Polignac number, because 23231531221 - 2⁵ = 23231531189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23231532221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11615765610 + 11615765611.

It is an arithmetic number, because the mean of its divisors is an integer number (11615765611).

Almost surely, 2^23231531221 is an apocalyptic number.

It is an amenable number.

23231531221 is a deficient number, since it is larger than the sum of its proper divisors (1).

23231531221 is an equidigital number, since it uses as much as digits as its factorization.

23231531221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2160, while the sum is 25.

The spelling of 23231531221 in words is "twenty-three billion, two hundred thirty-one million, five hundred thirty-one thousand, two hundred twenty-one".