861281208 has 128 divisors (see below), whose sum is σ = 2488320000. Its totient is φ = 275700096.

The previous prime is 861281203. The next prime is 861281209. The reversal of 861281208 is 802182168.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861281203) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2248585 + ... + 2248967.

It is an arithmetic number, because the mean of its divisors is an integer number (19440000).

Almost surely, 2^861281208 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 861281208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1244160000).

861281208 is an abundant number, since it is smaller than the sum of its proper divisors (1627038792).

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

861281208 is a wasteful number, since it uses less digits than its factorization.

861281208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 786 (or 776 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 36.

The square root of 861281208 is about 29347.5928825517. The cubic root of 861281208 is about 951.4405505930.

The spelling of 861281208 in words is "eight hundred sixty-one million, two hundred eighty-one thousand, two hundred eight".