66217544 has 8 divisors (see below), whose sum is σ = 124157910. Its totient is φ = 33108768.

The previous prime is 66217523. The next prime is 66217559. The reversal of 66217544 is 44571266.

66217544 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 33292900 + 32924644 = 5770^2 + 5738^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4138589 + ... + 4138604.

Almost surely, 2^66217544 is an apocalyptic number.

It is an amenable number.

66217544 is a deficient number, since it is larger than the sum of its proper divisors (57940366).

66217544 is a wasteful number, since it uses less digits than its factorization.

66217544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8277199 (or 8277195 counting only the distinct ones).

The product of its digits is 40320, while the sum is 35.

The square root of 66217544 is about 8137.4162975726. The cubic root of 66217544 is about 404.5675290109.

The spelling of 66217544 in words is "sixty-six million, two hundred seventeen thousand, five hundred forty-four".