66638855 has 8 divisors (see below), whose sum is σ = 80551152. Its totient is φ = 52921408.

The previous prime is 66638849. The next prime is 66638857. The reversal of 66638855 is 55883666.

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 66638855 - 2¹² = 66634759 is a prime.

It is a super-2 number, since 2×66638855² = 8881473991422050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66638857) 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, 47957 + ... + 49326.

It is an arithmetic number, because the mean of its divisors is an integer number (10068894).

Almost surely, 2^66638855 is an apocalyptic number.

66638855 is a deficient number, since it is larger than the sum of its proper divisors (13912297).

66638855 is a wasteful number, since it uses less digits than its factorization.

66638855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97425.

The product of its digits is 1036800, while the sum is 47.

The square root of 66638855 is about 8163.2625218107. The cubic root of 66638855 is about 405.4237398041.

The spelling of 66638855 in words is "sixty-six million, six hundred thirty-eight thousand, eight hundred fifty-five".