66615025 has 6 divisors (see below), whose sum is σ = 82602662. Its totient is φ = 53292000.

The previous prime is 66615013. The next prime is 66615047. The reversal of 66615025 is 52051666.

It can be written as a sum of positive squares in 3 ways, for example, as 17740944 + 48874081 = 4212^2 + 6991^2 .

It is not a de Polignac number, because 66615025 - 2⁷ = 66614897 is a prime.

It is a Duffinian 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 5 ways as a sum of consecutive naturals, for example, 1332276 + ... + 1332325.

Almost surely, 2^66615025 is an apocalyptic number.

It is an amenable number.

66615025 is a deficient number, since it is larger than the sum of its proper divisors (15987637).

66615025 is a wasteful number, since it uses less digits than its factorization.

66615025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2664611 (or 2664606 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 31.

The square root of 66615025 is about 8161.8028033027. The cubic root of 66615025 is about 405.3754076432.

The spelling of 66615025 in words is "sixty-six million, six hundred fifteen thousand, twenty-five".