66490251 has 4 divisors (see below), whose sum is σ = 88653672. Its totient is φ = 44326832.

The previous prime is 66490241. The next prime is 66490261. The reversal of 66490251 is 15209466.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (66490241) and next prime (66490261).

It is a cyclic number.

It is not a de Polignac number, because 66490251 - 2⁶ = 66490187 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66490231) 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 in 3 ways as a sum of consecutive naturals, for example, 11081706 + ... + 11081711.

It is an arithmetic number, because the mean of its divisors is an integer number (22163418).

Almost surely, 2^66490251 is an apocalyptic number.

66490251 is a deficient number, since it is larger than the sum of its proper divisors (22163421).

66490251 is a wasteful number, since it uses less digits than its factorization.

66490251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22163420.

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 66490251 is about 8154.1554436986. The cubic root of 66490251 is about 405.1221518449.

The spelling of 66490251 in words is "sixty-six million, four hundred ninety thousand, two hundred fifty-one".