66249985 has 4 divisors (see below), whose sum is σ = 79499988. Its totient is φ = 52999984.

The previous prime is 66249983. The next prime is 66250027. The reversal of 66249985 is 58994266.

66249985 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58994266 = 2 ⋅29497133.

It can be written as a sum of positive squares in 2 ways, for example, as 9684544 + 56565441 = 3112^2 + 7521^2 .

It is a cyclic number.

It is not a de Polignac number, because 66249985 - 2¹ = 66249983 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66249983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6624994 + ... + 6625003.

It is an arithmetic number, because the mean of its divisors is an integer number (19874997).

Almost surely, 2^66249985 is an apocalyptic number.

It is an amenable number.

66249985 is a deficient number, since it is larger than the sum of its proper divisors (13250003).

66249985 is a wasteful number, since it uses less digits than its factorization.

66249985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13250002.

The product of its digits is 933120, while the sum is 49.

The square root of 66249985 is about 8139.4093766071. The cubic root of 66249985 is about 404.6335861899.

The spelling of 66249985 in words is "sixty-six million, two hundred forty-nine thousand, nine hundred eighty-five".