66217844 has 24 divisors (see below), whose sum is σ = 144475968. Its totient is φ = 25799040.

The previous prime is 66217841. The next prime is 66217861. The reversal of 66217844 is 44871266.

It is a junction number, because it is equal to n+sod(n) for n = 66217798 and 66217807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66217841) 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, 107189 + ... + 107804.

It is an arithmetic number, because the mean of its divisors is an integer number (6019832).

Almost surely, 2^66217844 is an apocalyptic number.

It is an amenable number.

66217844 is an abundant number, since it is smaller than the sum of its proper divisors (78258124).

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

66217844 is a wasteful number, since it uses less digits than its factorization.

66217844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215015 (or 215013 counting only the distinct ones).

The product of its digits is 64512, while the sum is 38.

The square root of 66217844 is about 8137.4347309210. The cubic root of 66217844 is about 404.5681399772.

The spelling of 66217844 in words is "sixty-six million, two hundred seventeen thousand, eight hundred forty-four".