31523531525221 has 2 divisors, whose sum is σ = 31523531525222. Its totient is φ = 31523531525220.

The previous prime is 31523531525149. The next prime is 31523531525251. The reversal of 31523531525221 is 12252513532513.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26405466890625 + 5118064634596 = 5138625^2 + 2262314^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31523531525221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31523531525251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15761765762610 + 15761765762611.

It is an arithmetic number, because the mean of its divisors is an integer number (15761765762611).

Almost surely, 2^{31523531525221} is an apocalyptic number.

It is an amenable number.

31523531525221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31523531525221 is an equidigital number, since it uses as much as digits as its factorization.

31523531525221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 270000, while the sum is 40.

The spelling of 31523531525221 in words is "thirty-one trillion, five hundred twenty-three billion, five hundred thirty-one million, five hundred twenty-five thousand, two hundred twenty-one".