66081791 has 12 divisors (see below), whose sum is σ = 71332200. Its totient is φ = 61047360.

The previous prime is 66081779. The next prime is 66081793. The reversal of 66081791 is 19718066.

It is not a de Polignac number, because 66081791 - 2²² = 61887487 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 (66081793) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 30905 + ... + 32973.

It is an arithmetic number, because the mean of its divisors is an integer number (5944350).

Almost surely, 2^66081791 is an apocalyptic number.

66081791 is a deficient number, since it is larger than the sum of its proper divisors (5250409).

66081791 is a wasteful number, since it uses less digits than its factorization.

66081791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2170 (or 2129 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 66081791 is about 8129.0707340999. The cubic root of 66081791 is about 404.2908710603.

The spelling of 66081791 in words is "sixty-six million, eighty-one thousand, seven hundred ninety-one".