66038691 has 4 divisors (see below), whose sum is σ = 88051592. Its totient is φ = 44025792.

The previous prime is 66038683. The next prime is 66038767. The reversal of 66038691 is 19683066.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 66038691 - 2³ = 66038683 is a prime.

It is a super-2 number, since 2×66038691² = 8722217417986962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66038671) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11006446 + ... + 11006451.

It is an arithmetic number, because the mean of its divisors is an integer number (22012898).

Almost surely, 2^66038691 is an apocalyptic number.

66038691 is a deficient number, since it is larger than the sum of its proper divisors (22012901).

66038691 is a wasteful number, since it uses less digits than its factorization.

66038691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22012900.

The product of its (nonzero) digits is 46656, while the sum is 39.

The square root of 66038691 is about 8126.4193221861. The cubic root of 66038691 is about 404.2029561397.

The spelling of 66038691 in words is "sixty-six million, thirty-eight thousand, six hundred ninety-one".