31597706221 has 4 divisors (see below), whose sum is σ = 31598297244. Its totient is φ = 31597115200.

The previous prime is 31597706191. The next prime is 31597706227. The reversal of 31597706221 is 12260779513.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12260779513 = 701 ⋅17490413.

It can be written as a sum of positive squares in 2 ways, for example, as 13067690596 + 18530015625 = 114314^2 + 136125^2 .

It is a cyclic number.

It is not a de Polignac number, because 31597706221 - 2¹⁵ = 31597673453 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31597706227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 206350 + ... + 325231.

It is an arithmetic number, because the mean of its divisors is an integer number (7899574311).

Almost surely, 2^31597706221 is an apocalyptic number.

It is an amenable number.

31597706221 is a deficient number, since it is larger than the sum of its proper divisors (591023).

31597706221 is an equidigital number, since it uses as much as digits as its factorization.

31597706221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 591022.

The product of its (nonzero) digits is 158760, while the sum is 43.

The spelling of 31597706221 in words is "thirty-one billion, five hundred ninety-seven million, seven hundred six thousand, two hundred twenty-one".