866406840 has 128 divisors (see below), whose sum is σ = 2946585600. Its totient is φ = 202037760.

The previous prime is 866406833. The next prime is 866406991. The reversal of 866406840 is 48604668.

It is a junction number, because it is equal to n+sod(n) for n = 866406792 and 866406801.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 15025 + ... + 44255.

It is an arithmetic number, because the mean of its divisors is an integer number (23020200).

Almost surely, 2^866406840 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 866406840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1473292800).

866406840 is an abundant number, since it is smaller than the sum of its proper divisors (2080178760).

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

866406840 is a wasteful number, since it uses less digits than its factorization.

866406840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29277 (or 29273 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 42.

The square root of 866406840 is about 29434.7896204474. The cubic root of 866406840 is about 953.3242140824.

The spelling of 866406840 in words is "eight hundred sixty-six million, four hundred six thousand, eight hundred forty".