861172884 has 120 divisors (see below), whose sum is σ = 2644998048. Its totient is φ = 240874560.

The previous prime is 861172867. The next prime is 861172889. The reversal of 861172884 is 488271168.

861172884 is a `hidden beast` number, since 8 + 611 + 7 + 28 + 8 + 4 = 666.

It is a super-2 number, since 2×861172884² = 1483237472273754912, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861172889) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 37039 + ... + 55625.

Almost surely, 2^861172884 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 861172884, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1322499024).

861172884 is an abundant number, since it is smaller than the sum of its proper divisors (1783825164).

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

861172884 is a wasteful number, since it uses less digits than its factorization.

861172884 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18627 (or 18616 counting only the distinct ones).

The product of its digits is 172032, while the sum is 45.

The square root of 861172884 is about 29345.7472898545. The cubic root of 861172884 is about 951.4006611173.

The spelling of 861172884 in words is "eight hundred sixty-one million, one hundred seventy-two thousand, eight hundred eighty-four".