66942591 has 8 divisors (see below), whose sum is σ = 89313840. Its totient is φ = 44599872.

The previous prime is 66942541. The next prime is 66942607. The reversal of 66942591 is 19524966.

It is a happy number.

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

It is not a de Polignac number, because 66942591 - 2²¹ = 64845439 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66942511) 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, 870 + ... + 11603.

It is an arithmetic number, because the mean of its divisors is an integer number (11164230).

Almost surely, 2^66942591 is an apocalyptic number.

66942591 is a deficient number, since it is larger than the sum of its proper divisors (22371249).

66942591 is a wasteful number, since it uses less digits than its factorization.

66942591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14265.

The product of its digits is 116640, while the sum is 42.

The square root of 66942591 is about 8181.8452075311. The cubic root of 66942591 is about 406.0387722119.

The spelling of 66942591 in words is "sixty-six million, nine hundred forty-two thousand, five hundred ninety-one".