1231312217 has 2 divisors, whose sum is σ = 1231312218. Its totient is φ = 1231312216.

The previous prime is 1231312211. The next prime is 1231312259. The reversal of 1231312217 is 7122131321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 650454016 + 580858201 = 25504^2 + 24101^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231312217 - 2²⁰ = 1230263641 is a prime.

It is a super-2 number, since 2×1231312217² = 3032259551466910178, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1231312192 and 1231312201.

It is not a weakly prime, because it can be changed into another prime (1231312211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615656108 + 615656109.

It is an arithmetic number, because the mean of its divisors is an integer number (615656109).

Almost surely, 2^1231312217 is an apocalyptic number.

It is an amenable number.

1231312217 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231312217 is an equidigital number, since it uses as much as digits as its factorization.

1231312217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 504, while the sum is 23.

The square root of 1231312217 is about 35090.0586633878. The cubic root of 1231312217 is about 1071.8221541796.

Adding to 1231312217 its reverse (7122131321), we get a palindrome (8353443538).

The spelling of 1231312217 in words is "one billion, two hundred thirty-one million, three hundred twelve thousand, two hundred seventeen".