31125217 has 2 divisors, whose sum is σ = 31125218. Its totient is φ = 31125216.

The previous prime is 31125203. The next prime is 31125221. The reversal of 31125217 is 71252113.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30459361 + 665856 = 5519^2 + 816^2 .

It is an emirp because it is prime and its reverse (71252113) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31125217 - 2¹⁵ = 31092449 is a prime.

It is not a weakly prime, because it can be changed into another prime (31125247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15562608 + 15562609.

It is an arithmetic number, because the mean of its divisors is an integer number (15562609).

Almost surely, 2^31125217 is an apocalyptic number.

It is an amenable number.

31125217 is a deficient number, since it is larger than the sum of its proper divisors (1).

31125217 is an equidigital number, since it uses as much as digits as its factorization.

31125217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 420, while the sum is 22.

The square root of 31125217 is about 5578.9978490765. The cubic root of 31125217 is about 314.5604586011.

It can be divided in two parts, 311 and 25217, that multiplied together give a palindrome (7842487).

The spelling of 31125217 in words is "thirty-one million, one hundred twenty-five thousand, two hundred seventeen".