866860646400 has 810 divisors, whose sum is σ = 3612915633600. Its totient is φ = 198098288640.

The previous prime is 866860646389. The next prime is 866860646417. The reversal of 866860646400 is 4646068668.

866860646400 is a `hidden beast` number, since 86 + 68 + 60 + 6 + 46 + 400 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 180631201 + ... + 180635999.

Almost surely, 2^866860646400 is an apocalyptic number.

866860646400 is a gapful number since it is divisible by the number (80) 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 866860646400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1806457816800).

866860646400 is an abundant number, since it is smaller than the sum of its proper divisors (2746054987200).

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

866860646400 is a wasteful number, since it uses less digits than its factorization.

866860646400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4857 (or 4816 counting only the distinct ones).

The product of its (nonzero) digits is 7962624, while the sum is 54.

The spelling of 866860646400 in words is "eight hundred sixty-six billion, eight hundred sixty million, six hundred forty-six thousand, four hundred".