221021315231 has 2 divisors, whose sum is σ = 221021315232. Its totient is φ = 221021315230.

The previous prime is 221021315209. The next prime is 221021315237. The reversal of 221021315231 is 132513120122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221021315231 - 2⁶ = 221021315167 is a prime.

It is a super-2 number, since 2×221021315231² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 221021315197 and 221021315206.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221021315237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110510657615 + 110510657616.

It is an arithmetic number, because the mean of its divisors is an integer number (110510657616).

Almost surely, 2^221021315231 is an apocalyptic number.

221021315231 is a deficient number, since it is larger than the sum of its proper divisors (1).

221021315231 is an equidigital number, since it uses as much as digits as its factorization.

221021315231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 23.

Adding to 221021315231 its reverse (132513120122), we get a palindrome (353534435353).

The spelling of 221021315231 in words is "two hundred twenty-one billion, twenty-one million, three hundred fifteen thousand, two hundred thirty-one".