31000002221 has 2 divisors, whose sum is σ = 31000002222. Its totient is φ = 31000002220.

The previous prime is 31000002211. The next prime is 31000002223. The reversal of 31000002221 is 12220000013.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23366485321 + 7633516900 = 152861^2 + 87370^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31000002221 is a prime.

It is a super-2 number, since 2×31000002221² (a number of 22 digits) contains 22 as substring.

Together with 31000002223, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31000002223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15500001110 + 15500001111.

It is an arithmetic number, because the mean of its divisors is an integer number (15500001111).

Almost surely, 2^31000002221 is an apocalyptic number.

It is an amenable number.

31000002221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31000002221 is an equidigital number, since it uses as much as digits as its factorization.

31000002221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24, while the sum is 11.

Adding to 31000002221 its reverse (12220000013), we get a palindrome (43220002234).

The spelling of 31000002221 in words is "thirty-one billion, two thousand, two hundred twenty-one".