217140251 has 2 divisors, whose sum is σ = 217140252. Its totient is φ = 217140250.

The previous prime is 217140211. The next prime is 217140257. The reversal of 217140251 is 152041712.

217140251 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 217140251 - 2¹⁴ = 217123867 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (217140257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108570125 + 108570126.

It is an arithmetic number, because the mean of its divisors is an integer number (108570126).

Almost surely, 2^217140251 is an apocalyptic number.

217140251 is a deficient number, since it is larger than the sum of its proper divisors (1).

217140251 is an equidigital number, since it uses as much as digits as its factorization.

217140251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 560, while the sum is 23.

The square root of 217140251 is about 14735.6795228452. The cubic root of 217140251 is about 601.0539355787.

Adding to 217140251 its reverse (152041712), we get a palindrome (369181963).

The spelling of 217140251 in words is "two hundred seventeen million, one hundred forty thousand, two hundred fifty-one".