66441691 has 8 divisors (see below), whose sum is σ = 68050944. Its totient is φ = 64840680.

The previous prime is 66441659. The next prime is 66441703. The reversal of 66441691 is 19614466.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66441691 - 2⁵ = 66441659 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66441691.

It is not an unprimeable number, because it can be changed into a prime (66441631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16156 + ... + 19846.

It is an arithmetic number, because the mean of its divisors is an integer number (8506368).

Almost surely, 2^66441691 is an apocalyptic number.

66441691 is a deficient number, since it is larger than the sum of its proper divisors (1609253).

66441691 is a wasteful number, since it uses less digits than its factorization.

66441691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4121.

The product of its digits is 31104, while the sum is 37.

The square root of 66441691 is about 8151.1772769337. The cubic root of 66441691 is about 405.0235031831.

The spelling of 66441691 in words is "sixty-six million, four hundred forty-one thousand, six hundred ninety-one".