66544491 has 16 divisors (see below), whose sum is σ = 95723264. Its totient is φ = 40876704.

The previous prime is 66544487. The next prime is 66544493. The reversal of 66544491 is 19444566.

It is not a de Polignac number, because 66544491 - 2² = 66544487 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (66544493) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27180 + ... + 29526.

It is an arithmetic number, because the mean of its divisors is an integer number (5982704).

Almost surely, 2^66544491 is an apocalyptic number.

66544491 is a deficient number, since it is larger than the sum of its proper divisors (29178773).

66544491 is a wasteful number, since it uses less digits than its factorization.

66544491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3090.

The product of its digits is 103680, while the sum is 39.

The square root of 66544491 is about 8157.4806772680. The cubic root of 66544491 is about 405.2322825421.

The spelling of 66544491 in words is "sixty-six million, five hundred forty-four thousand, four hundred ninety-one".