66615005 has 4 divisors (see below), whose sum is σ = 79938012. Its totient is φ = 53292000.

The previous prime is 66614981. The next prime is 66615013. The reversal of 66615005 is 50051666.

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

It can be written as a sum of positive squares in 2 ways, for example, as 17530969 + 49084036 = 4187^2 + 7006^2 .

It is not a de Polignac number, because 66615005 - 2⁸ = 66614749 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6661496 + ... + 6661505.

It is an arithmetic number, because the mean of its divisors is an integer number (19984503).

Almost surely, 2^66615005 is an apocalyptic number.

It is an amenable number.

66615005 is a deficient number, since it is larger than the sum of its proper divisors (13323007).

66615005 is a wasteful number, since it uses less digits than its factorization.

66615005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13323006.

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 66615005 is about 8161.8015780831. The cubic root of 66615005 is about 405.3753670743.

The spelling of 66615005 in words is "sixty-six million, six hundred fifteen thousand, five".