221864320831 has 2 divisors, whose sum is σ = 221864320832. Its totient is φ = 221864320830.

The previous prime is 221864320829. The next prime is 221864320849. The reversal of 221864320831 is 138023468122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221864320831 - 2¹ = 221864320829 is a prime.

It is a super-2 number, since 2×221864320831² (a number of 23 digits) contains 22 as substring.

Together with 221864320829, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221864320871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110932160415 + 110932160416.

It is an arithmetic number, because the mean of its divisors is an integer number (110932160416).

Almost surely, 2^221864320831 is an apocalyptic number.

221864320831 is a deficient number, since it is larger than the sum of its proper divisors (1).

221864320831 is an equidigital number, since it uses as much as digits as its factorization.

221864320831 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 110592, while the sum is 40.

Adding to 221864320831 its reverse (138023468122), we get a palindrome (359887788953).

The spelling of 221864320831 in words is "two hundred twenty-one billion, eight hundred sixty-four million, three hundred twenty thousand, eight hundred thirty-one".