1231131217 has 2 divisors, whose sum is σ = 1231131218. Its totient is φ = 1231131216.

The previous prime is 1231131199. The next prime is 1231131233. The reversal of 1231131217 is 7121311321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 979940416 + 251190801 = 31304^2 + 15849^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231131217 - 2⁷ = 1231131089 is a prime.

It is not a weakly prime, because it can be changed into another prime (1231131247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615565608 + 615565609.

It is an arithmetic number, because the mean of its divisors is an integer number (615565609).

Almost surely, 2^1231131217 is an apocalyptic number.

It is an amenable number.

1231131217 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231131217 is an equidigital number, since it uses as much as digits as its factorization.

1231131217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 252, while the sum is 22.

The square root of 1231131217 is about 35087.4794905533. The cubic root of 1231131217 is about 1071.7696331608.

Adding to 1231131217 its reverse (7121311321), we get a palindrome (8352442538).

The spelling of 1231131217 in words is "one billion, two hundred thirty-one million, one hundred thirty-one thousand, two hundred seventeen".