217500131 has 2 divisors, whose sum is σ = 217500132. Its totient is φ = 217500130.

The previous prime is 217500119. The next prime is 217500139. The reversal of 217500131 is 131005712.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217500131 is a prime.

It is a super-2 number, since 2×217500131² = 94612613970034322, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (217500139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108750065 + 108750066.

It is an arithmetic number, because the mean of its divisors is an integer number (108750066).

Almost surely, 2^217500131 is an apocalyptic number.

217500131 is a deficient number, since it is larger than the sum of its proper divisors (1).

217500131 is an equidigital number, since it uses as much as digits as its factorization.

217500131 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 210, while the sum is 20.

The square root of 217500131 is about 14747.8856450679. The cubic root of 217500131 is about 601.3858069528.

Adding to 217500131 its reverse (131005712), we get a palindrome (348505843).

The spelling of 217500131 in words is "two hundred seventeen million, five hundred thousand, one hundred thirty-one".