66210251 has 2 divisors, whose sum is σ = 66210252. Its totient is φ = 66210250.

The previous prime is 66210191. The next prime is 66210253. The reversal of 66210251 is 15201266.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66210251 is a prime.

Together with 66210253, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66210253) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33105125 + 33105126.

It is an arithmetic number, because the mean of its divisors is an integer number (33105126).

Almost surely, 2^66210251 is an apocalyptic number.

66210251 is a deficient number, since it is larger than the sum of its proper divisors (1).

66210251 is an equidigital number, since it uses as much as digits as its factorization.

66210251 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 66210251 is about 8136.9681700250. The cubic root of 66210251 is about 404.5526758509.

The spelling of 66210251 in words is "sixty-six million, two hundred ten thousand, two hundred fifty-one".