861389100 has 576 divisors, whose sum is σ = 3429780480. Its totient is φ = 182476800.

The previous prime is 861389047. The next prime is 861389101. The reversal of 861389100 is 1983168.

861389100 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not an unprimeable number, because it can be changed into a prime (861389101) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 8880252 + ... + 8880348.

It is an arithmetic number, because the mean of its divisors is an integer number (5954480).

Almost surely, 2^861389100 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 861389100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1714890240).

861389100 is an abundant number, since it is smaller than the sum of its proper divisors (2568391380).

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

861389100 is a wasteful number, since it uses less digits than its factorization.

861389100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167 (or 154 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 861389100 is about 29349.4309995952. The cubic root of 861389100 is about 951.4802776635.

The spelling of 861389100 in words is "eight hundred sixty-one million, three hundred eighty-nine thousand, one hundred".