217145953 has 2 divisors, whose sum is σ = 217145954. Its totient is φ = 217145952.

The previous prime is 217145923. The next prime is 217145977. The reversal of 217145953 is 359541712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 149132944 + 68013009 = 12212^2 + 8247^2 .

It is a cyclic number.

It is not a de Polignac number, because 217145953 - 2⁹ = 217145441 is a prime.

It is not a weakly prime, because it can be changed into another prime (217145923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108572976 + 108572977.

It is an arithmetic number, because the mean of its divisors is an integer number (108572977).

Almost surely, 2^217145953 is an apocalyptic number.

It is an amenable number.

217145953 is a deficient number, since it is larger than the sum of its proper divisors (1).

217145953 is an equidigital number, since it uses as much as digits as its factorization.

217145953 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 37800, while the sum is 37.

The square root of 217145953 is about 14735.8729975526. The cubic root of 217145953 is about 601.0591966630.

The spelling of 217145953 in words is "two hundred seventeen million, one hundred forty-five thousand, nine hundred fifty-three".