31031131217 has 2 divisors, whose sum is σ = 31031131218. Its totient is φ = 31031131216.

The previous prime is 31031131213. The next prime is 31031131231. The reversal of 31031131217 is 71213113013.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20904533056 + 10126598161 = 144584^2 + 100631^2 .

It is a cyclic number.

It is not a de Polignac number, because 31031131217 - 2² = 31031131213 is a prime.

It is a super-2 number, since 2×31031131217² (a number of 22 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31031131192 and 31031131201.

It is not a weakly prime, because it can be changed into another prime (31031131211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15515565608 + 15515565609.

It is an arithmetic number, because the mean of its divisors is an integer number (15515565609).

Almost surely, 2^31031131217 is an apocalyptic number.

It is an amenable number.

31031131217 is a deficient number, since it is larger than the sum of its proper divisors (1).

31031131217 is an equidigital number, since it uses as much as digits as its factorization.

31031131217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 378, while the sum is 23.

The spelling of 31031131217 in words is "thirty-one billion, thirty-one million, one hundred thirty-one thousand, two hundred seventeen".