66632591 has 4 divisors (see below), whose sum is σ = 66737184. Its totient is φ = 66528000.

The previous prime is 66632581. The next prime is 66632593. The reversal of 66632591 is 19523666.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66632591 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66632593) 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, 51335 + ... + 52616.

It is an arithmetic number, because the mean of its divisors is an integer number (16684296).

Almost surely, 2^66632591 is an apocalyptic number.

66632591 is a deficient number, since it is larger than the sum of its proper divisors (104593).

66632591 is a wasteful number, since it uses less digits than its factorization.

66632591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104592.

The product of its digits is 58320, while the sum is 38.

The square root of 66632591 is about 8162.8788426633. The cubic root of 66632591 is about 405.4110362350.

The spelling of 66632591 in words is "sixty-six million, six hundred thirty-two thousand, five hundred ninety-one".