866491610400 has 864 divisors, whose sum is σ = 3500090979840. Its totient is φ = 199941488640.

The previous prime is 866491610297. The next prime is 866491610423. The reversal of 866491610400 is 4016194668.

866491610400 is a `hidden beast` number, since 8 + 66 + 491 + 61 + 0 + 40 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 172502289 + ... + 172507311.

Almost surely, 2^866491610400 is an apocalyptic number.

866491610400 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 866491610400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1750045489920).

866491610400 is an abundant number, since it is smaller than the sum of its proper divisors (2633599369440).

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

866491610400 is a wasteful number, since it uses less digits than its factorization.

866491610400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5178 (or 5162 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The spelling of 866491610400 in words is "eight hundred sixty-six billion, four hundred ninety-one million, six hundred ten thousand, four hundred".