66615506 has 8 divisors (see below), whose sum is σ = 100000764. Its totient is φ = 33281920.

The previous prime is 66615499. The next prime is 66615509. The reversal of 66615506 is 60551666.

It can be written as a sum of positive squares in 2 ways, for example, as 66569281 + 46225 = 8159^2 + 215^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66615509) 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, 9515 + ... + 14958.

Almost surely, 2^66615506 is an apocalyptic number.

66615506 is a deficient number, since it is larger than the sum of its proper divisors (33385258).

66615506 is a wasteful number, since it uses less digits than its factorization.

66615506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25836.

The product of its (nonzero) digits is 32400, while the sum is 35.

The square root of 66615506 is about 8161.8322697786. The cubic root of 66615506 is about 405.3763833245.

It can be divided in two parts, 6661 and 5506, that added together give a cube (12167 = 23³).

The spelling of 66615506 in words is "sixty-six million, six hundred fifteen thousand, five hundred six".