66690725 has 12 divisors (see below), whose sum is σ = 83047140. Its totient is φ = 53126400.

The previous prime is 66690719. The next prime is 66690733. The reversal of 66690725 is 52709666.

It can be written as a sum of positive squares in 6 ways, for example, as 3996001 + 62694724 = 1999^2 + 7918^2 .

It is not a de Polignac number, because 66690725 - 2²⁰ = 65642149 is a prime.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 491 + ... + 11559.

It is an arithmetic number, because the mean of its divisors is an integer number (6920595).

Almost surely, 2^66690725 is an apocalyptic number.

It is an amenable number.

66690725 is a deficient number, since it is larger than the sum of its proper divisors (16356415).

66690725 is a wasteful number, since it uses less digits than its factorization.

66690725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11320 (or 11315 counting only the distinct ones).

The product of its (nonzero) digits is 136080, while the sum is 41.

The square root of 66690725 is about 8166.4389424032. The cubic root of 66690725 is about 405.5289030531.

The spelling of 66690725 in words is "sixty-six million, six hundred ninety thousand, seven hundred twenty-five".