217021253 has 2 divisors, whose sum is σ = 217021254. Its totient is φ = 217021252.

The previous prime is 217021237. The next prime is 217021279. The reversal of 217021253 is 352120712.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 127283524 + 89737729 = 11282^2 + 9473^2 .

It is a cyclic number.

It is not a de Polignac number, because 217021253 - 2⁴ = 217021237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (217021853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108510626 + 108510627.

It is an arithmetic number, because the mean of its divisors is an integer number (108510627).

Almost surely, 2^217021253 is an apocalyptic number.

It is an amenable number.

217021253 is a deficient number, since it is larger than the sum of its proper divisors (1).

217021253 is an equidigital number, since it uses as much as digits as its factorization.

217021253 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 217021253 is about 14731.6412188188. The cubic root of 217021253 is about 600.9441182516.

Adding to 217021253 its reverse (352120712), we get a palindrome (569141965).

The spelling of 217021253 in words is "two hundred seventeen million, twenty-one thousand, two hundred fifty-three".