866444544 has 216 divisors, whose sum is σ = 2948854272. Its totient is φ = 239431680.

The previous prime is 866444533. The next prime is 866444567. The reversal of 866444544 is 445444668.

866444544 is a `hidden beast` number, since 8 + 6 + 64 + 44 + 544 = 666.

It is a super-2 number, since 2×866444544² = 1501452295654735872, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 866444544.

It is a congruent number.

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, 499102 + ... + 500834.

Almost surely, 2^866444544 is an apocalyptic number.

866444544 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 866444544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1474427136).

866444544 is an abundant number, since it is smaller than the sum of its proper divisors (2082409728).

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

866444544 is a wasteful number, since it uses less digits than its factorization.

866444544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1793 (or 1776 counting only the distinct ones).

The product of its digits is 1474560, while the sum is 45.

The square root of 866444544 is about 29435.4300800923. The cubic root of 866444544 is about 953.3380426955.

The spelling of 866444544 in words is "eight hundred sixty-six million, four hundred forty-four thousand, five hundred forty-four".