66666444 has 72 divisors (see below), whose sum is σ = 171182592. Its totient is φ = 20180160.

The previous prime is 66666437. The next prime is 66666487. The reversal of 66666444 is 44466666.

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

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 66666396 and 66666405.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 143757 + ... + 144219.

It is an arithmetic number, because the mean of its divisors is an integer number (2377536).

Almost surely, 2^66666444 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 66666444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85591296).

66666444 is an abundant number, since it is smaller than the sum of its proper divisors (104516148).

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

66666444 is a wasteful number, since it uses less digits than its factorization.

66666444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 567 (or 552 counting only the distinct ones).

The product of its digits is 497664, while the sum is 42.

The square root of 66666444 is about 8164.9521737730. The cubic root of 66666444 is about 405.4796816032.

The spelling of 66666444 in words is "sixty-six million, six hundred sixty-six thousand, four hundred forty-four".