866623212 has 540 divisors, whose sum is σ = 3180620520. Its totient is φ = 203793408.

The previous prime is 866623133. The next prime is 866623301. The reversal of 866623212 is 212326668.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 179 ways as a sum of consecutive naturals, for example, 45611739 + ... + 45611757.

It is an arithmetic number, because the mean of its divisors is an integer number (5890038).

Almost surely, 2^866623212 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 866623212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1590310260).

866623212 is an abundant number, since it is smaller than the sum of its proper divisors (2313997308).

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

866623212 is a wasteful number, since it uses less digits than its factorization.

866623212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92 (or 61 counting only the distinct ones).

The product of its digits is 41472, while the sum is 36.

The square root of 866623212 is about 29438.4648376915. The cubic root of 866623212 is about 953.4035669101.

It can be divided in two parts, 8666 and 23212, that added together give a triangular number (31878 = T₂₅₂).

The spelling of 866623212 in words is "eight hundred sixty-six million, six hundred twenty-three thousand, two hundred twelve".