66744891 has 40 divisors (see below), whose sum is σ = 108416000. Its totient is φ = 40765680.

The previous prime is 66744877. The next prime is 66744911. The reversal of 66744891 is 19844766.

It is not a de Polignac number, because 66744891 - 2⁵ = 66744859 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 (66744851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 47010 + ... + 48408.

It is an arithmetic number, because the mean of its divisors is an integer number (2710400).

Almost surely, 2^66744891 is an apocalyptic number.

66744891 is a deficient number, since it is larger than the sum of its proper divisors (41671109).

66744891 is a wasteful number, since it uses less digits than its factorization.

66744891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1461 (or 1452 counting only the distinct ones).

The product of its digits is 290304, while the sum is 45.

The square root of 66744891 is about 8169.7546474787. The cubic root of 66744891 is about 405.6386631153.

The spelling of 66744891 in words is "sixty-six million, seven hundred forty-four thousand, eight hundred ninety-one".