31000032221 has 2 divisors, whose sum is σ = 31000032222. Its totient is φ = 31000032220.

The previous prime is 31000032197. The next prime is 31000032229. The reversal of 31000032221 is 12223000013.

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., 30979872121 + 20160100 = 176011^2 + 4490^2 .

It is a cyclic number.

It is not a de Polignac number, because 31000032221 - 2⁶ = 31000032157 is a prime.

It is a super-2 number, since 2×31000032221² (a number of 22 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31000032196 and 31000032205.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31000032229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15500016110 + 15500016111.

It is an arithmetic number, because the mean of its divisors is an integer number (15500016111).

Almost surely, 2^31000032221 is an apocalyptic number.

It is an amenable number.

31000032221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31000032221 is an equidigital number, since it uses as much as digits as its factorization.

31000032221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 14.

Adding to 31000032221 its reverse (12223000013), we get a palindrome (43223032234).

The spelling of 31000032221 in words is "thirty-one billion, thirty-two thousand, two hundred twenty-one".