861251040 has 216 divisors, whose sum is σ = 3183387480. Its totient is φ = 211940352.

The previous prime is 861250993. The next prime is 861251047. The reversal of 861251040 is 40152168.

861251040 is a `hidden beast` number, since 8 + 612 + 5 + 1 + 0 + 40 = 666.

861251040 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 861250995 and 861251013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861251047) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 241591 + ... + 245129.

It is an arithmetic number, because the mean of its divisors is an integer number (14737905).

Almost surely, 2^861251040 is an apocalyptic number.

861251040 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 861251040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1591693740).

861251040 is an abundant number, since it is smaller than the sum of its proper divisors (2322136440).

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

861251040 is a wasteful number, since it uses less digits than its factorization.

861251040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3586 (or 3562 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 861251040 is about 29347.0789006334. The cubic root of 861251040 is about 951.4294417962.

The spelling of 861251040 in words is "eight hundred sixty-one million, two hundred fifty-one thousand, forty".