66664224 has 108 divisors (see below), whose sum is σ = 208486278. Its totient is φ = 20190720.

The previous prime is 66664223. The next prime is 66664231. The reversal of 66664224 is 42246666.

66664224 = T₄₃₁ + T₄₃₂ + ... + T₇₈₂.

It can be written as a sum of positive squares in only one way, i.e., 45319824 + 21344400 = 6732^2 + 4620^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (66664223) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 33892 + ... + 35804.

Almost surely, 2^66664224 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66664224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104243139).

66664224 is an abundant number, since it is smaller than the sum of its proper divisors (141822054).

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

66664224 is a wasteful number, since it uses less digits than its factorization.

66664224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1951 (or 1929 counting only the distinct ones).

The product of its digits is 82944, while the sum is 36.

The square root of 66664224 is about 8164.8162257334. The cubic root of 66664224 is about 405.4751807137.

It can be divided in two parts, 666642 and 24, that added together give a palindrome (666666).

The spelling of 66664224 in words is "sixty-six million, six hundred sixty-four thousand, two hundred twenty-four".