666244644 has 96 divisors (see below), whose sum is σ = 1732106880. Its totient is φ = 199165824.

The previous prime is 666244643. The next prime is 666244651. The reversal of 666244644 is 446442666.

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

It is a junction number, because it is equal to n+sod(n) for n = 666244596 and 666244605.

It is not an unprimeable number, because it can be changed into a prime (666244643) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 975127 + ... + 975809.

It is an arithmetic number, because the mean of its divisors is an integer number (18042780).

Almost surely, 2^666244644 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 666244644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (866053440).

666244644 is an abundant number, since it is smaller than the sum of its proper divisors (1065862236).

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

666244644 is a wasteful number, since it uses less digits than its factorization.

666244644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 766 (or 738 counting only the distinct ones).

The product of its digits is 663552, while the sum is 42.

The square root of 666244644 is about 25811.7152471509. The cubic root of 666244644 is about 873.3960904471.

The spelling of 666244644 in words is "six hundred sixty-six million, two hundred forty-four thousand, six hundred forty-four".