31301312221 has 2 divisors, whose sum is σ = 31301312222. Its totient is φ = 31301312220.

The previous prime is 31301312183. The next prime is 31301312233. The reversal of 31301312221 is 12221310313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31157192196 + 144120025 = 176514^2 + 12005^2 .

It is a cyclic number.

It is not a de Polignac number, because 31301312221 - 2¹⁵ = 31301279453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31301312621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15650656110 + 15650656111.

It is an arithmetic number, because the mean of its divisors is an integer number (15650656111).

Almost surely, 2^31301312221 is an apocalyptic number.

It is an amenable number.

31301312221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31301312221 is an equidigital number, since it uses as much as digits as its factorization.

31301312221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 31301312221 its reverse (12221310313), we get a palindrome (43522622534).

The spelling of 31301312221 in words is "thirty-one billion, three hundred one million, three hundred twelve thousand, two hundred twenty-one".