66501887 has 4 divisors (see below), whose sum is σ = 66737160. Its totient is φ = 66266616.

The previous prime is 66501863. The next prime is 66501889. The reversal of 66501887 is 78810566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78810566 = 2 ⋅39405283.

It is a cyclic number.

It is not a de Polignac number, because 66501887 - 2⁶ = 66501823 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 (66501889) 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, 117212 + ... + 117777.

It is an arithmetic number, because the mean of its divisors is an integer number (16684290).

Almost surely, 2^66501887 is an apocalyptic number.

66501887 is a deficient number, since it is larger than the sum of its proper divisors (235273).

66501887 is a wasteful number, since it uses less digits than its factorization.

66501887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235272.

The product of its (nonzero) digits is 80640, while the sum is 41.

The square root of 66501887 is about 8154.8689137226. The cubic root of 66501887 is about 405.1457830105.

The spelling of 66501887 in words is "sixty-six million, five hundred one thousand, eight hundred eighty-seven".