66619791 has 24 divisors (see below), whose sum is σ = 111845760. Its totient is φ = 37421136.

The previous prime is 66619789. The next prime is 66619801. The reversal of 66619791 is 19791666.

It is not a de Polignac number, because 66619791 - 2¹ = 66619789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66619291) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5245 + ... + 12678.

It is an arithmetic number, because the mean of its divisors is an integer number (4660240).

Almost surely, 2^66619791 is an apocalyptic number.

66619791 is a deficient number, since it is larger than the sum of its proper divisors (45225969).

66619791 is a wasteful number, since it uses less digits than its factorization.

66619791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17995 (or 17992 counting only the distinct ones).

The product of its digits is 122472, while the sum is 45.

The square root of 66619791 is about 8162.0947678889. The cubic root of 66619791 is about 405.3850749974.

The spelling of 66619791 in words is "sixty-six million, six hundred nineteen thousand, seven hundred ninety-one".