66866155 has 4 divisors (see below), whose sum is σ = 80239392. Its totient is φ = 53492920.

The previous prime is 66866131. The next prime is 66866171. The reversal of 66866155 is 55166866.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55166866 = 2 ⋅27583433.

It is not a de Polignac number, because 66866155 - 2⁵ = 66866123 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6686611 + ... + 6686620.

It is an arithmetic number, because the mean of its divisors is an integer number (20059848).

Almost surely, 2^66866155 is an apocalyptic number.

66866155 is a deficient number, since it is larger than the sum of its proper divisors (13373237).

66866155 is a wasteful number, since it uses less digits than its factorization.

66866155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13373236.

The product of its digits is 259200, while the sum is 43.

The square root of 66866155 is about 8177.1727999352. The cubic root of 66866155 is about 405.8841730791.

The spelling of 66866155 in words is "sixty-six million, eight hundred sixty-six thousand, one hundred fifty-five".