66556818 has 24 divisors (see below), whose sum is σ = 144655056. Its totient is φ = 22116600.

The previous prime is 66556813. The next prime is 66556823. The reversal of 66556818 is 81865566.

It is an interprime number because it is at equal distance from previous prime (66556813) and next prime (66556823).

It is not an unprimeable number, because it can be changed into a prime (66556813) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 373 + ... + 11543.

It is an arithmetic number, because the mean of its divisors is an integer number (6027294).

Almost surely, 2^66556818 is an apocalyptic number.

66556818 is an abundant number, since it is smaller than the sum of its proper divisors (78098238).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66556818 is a wasteful number, since it uses less digits than its factorization.

66556818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11510 (or 11507 counting only the distinct ones).

The product of its digits is 345600, while the sum is 45.

The square root of 66556818 is about 8158.2362064358. The cubic root of 66556818 is about 405.2573033458.

The spelling of 66556818 in words is "sixty-six million, five hundred fifty-six thousand, eight hundred eighteen".