861887880 has 384 divisors, whose sum is σ = 3450470400. Its totient is φ = 182186496.

The previous prime is 861887863. The next prime is 861887891. The reversal of 861887880 is 88788168.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2250169 + ... + 2250551.

It is an arithmetic number, because the mean of its divisors is an integer number (8985600).

Almost surely, 2^861887880 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 861887880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1725235200).

861887880 is an abundant number, since it is smaller than the sum of its proper divisors (2588582520).

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

861887880 is a wasteful number, since it uses less digits than its factorization.

861887880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 473 (or 466 counting only the distinct ones).

The product of its (nonzero) digits is 1376256, while the sum is 54.

The square root of 861887880 is about 29357.9270385359. The cubic root of 861887880 is about 951.6638910704.

The spelling of 861887880 in words is "eight hundred sixty-one million, eight hundred eighty-seven thousand, eight hundred eighty".