66624251 has 4 divisors (see below), whose sum is σ = 66689904. Its totient is φ = 66558600.

The previous prime is 66624227. The next prime is 66624269. The reversal of 66624251 is 15242666.

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

It is a cyclic number.

It is not a de Polignac number, because 66624251 - 2²² = 62429947 is a prime.

It is a super-2 number, since 2×66624251² = 8877581642622002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66624451) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31280 + ... + 33341.

It is an arithmetic number, because the mean of its divisors is an integer number (16672476).

Almost surely, 2^66624251 is an apocalyptic number.

66624251 is a deficient number, since it is larger than the sum of its proper divisors (65653).

66624251 is a wasteful number, since it uses less digits than its factorization.

66624251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65652.

The product of its digits is 17280, while the sum is 32.

The square root of 66624251 is about 8162.3679774928. The cubic root of 66624251 is about 405.3941212436.

The spelling of 66624251 in words is "sixty-six million, six hundred twenty-four thousand, two hundred fifty-one".