861001187 has 4 divisors (see below), whose sum is σ = 861600960. Its totient is φ = 860401416.

The previous prime is 861001157. The next prime is 861001217. The reversal of 861001187 is 781100168.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (861001157) and next prime (861001217).

It is a cyclic number.

It is not a de Polignac number, because 861001187 - 2¹⁶ = 860935651 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (861001157) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 297728 + ... + 300605.

It is an arithmetic number, because the mean of its divisors is an integer number (215400240).

Almost surely, 2^861001187 is an apocalyptic number.

861001187 is a deficient number, since it is larger than the sum of its proper divisors (599773).

861001187 is a wasteful number, since it uses less digits than its factorization.

861001187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 599772.

The product of its (nonzero) digits is 2688, while the sum is 32.

The square root of 861001187 is about 29342.8217286613. The cubic root of 861001187 is about 951.3374281708.

The spelling of 861001187 in words is "eight hundred sixty-one million, one thousand, one hundred eighty-seven".