866642427840 has 1344 divisors, whose sum is σ = 3517528550400. Its totient is φ = 179589021696.

The previous prime is 866642427809. The next prime is 866642427853. The reversal of 866642427840 is 48724246668.

It is a tau number, because it is divible by the number of its divisors (1344).

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 2414045581 + ... + 2414045939.

Almost surely, 2^866642427840 is an apocalyptic number.

866642427840 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 866642427840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1758764275200).

866642427840 is an abundant number, since it is smaller than the sum of its proper divisors (2650886122560).

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

866642427840 is a wasteful number, since it uses less digits than its factorization.

866642427840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 522 (or 505 counting only the distinct ones).

The product of its (nonzero) digits is 24772608, while the sum is 57.

The spelling of 866642427840 in words is "eight hundred sixty-six billion, six hundred forty-two million, four hundred twenty-seven thousand, eight hundred forty".