66217884 has 12 divisors (see below), whose sum is σ = 154508424. Its totient is φ = 22072624.

The previous prime is 66217867. The next prime is 66217889. The reversal of 66217884 is 48871266.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×66217884² = 8769616322874912, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66217889) 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, 2759067 + ... + 2759090.

It is an arithmetic number, because the mean of its divisors is an integer number (12875702).

Almost surely, 2^66217884 is an apocalyptic number.

It is an amenable number.

66217884 is an abundant number, since it is smaller than the sum of its proper divisors (88290540).

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

66217884 is a wasteful number, since it uses less digits than its factorization.

66217884 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5518164 (or 5518162 counting only the distinct ones).

The product of its digits is 129024, while the sum is 42.

The square root of 66217884 is about 8137.4371886977. The cubic root of 66217884 is about 404.5682214393.

The spelling of 66217884 in words is "sixty-six million, two hundred seventeen thousand, eight hundred eighty-four".