861492987 has 12 divisors (see below), whose sum is σ = 1257208680. Its totient is φ = 568407168.

The previous prime is 861492959. The next prime is 861493019. The reversal of 861492987 is 789294168.

861492987 is a `hidden beast` number, since 8 + 61 + 492 + 98 + 7 = 666.

It is not a de Polignac number, because 861492987 - 2⁶ = 861492923 is a prime.

It is not an unprimeable number, because it can be changed into a prime (861499987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 492537 + ... + 494282.

It is an arithmetic number, because the mean of its divisors is an integer number (104767390).

Almost surely, 2^861492987 is an apocalyptic number.

861492987 is a deficient number, since it is larger than the sum of its proper divisors (395715693).

861492987 is a wasteful number, since it uses less digits than its factorization.

861492987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 986922 (or 986919 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 54.

The square root of 861492987 is about 29351.2007761182. The cubic root of 861492987 is about 951.5185269123.

The spelling of 861492987 in words is "eight hundred sixty-one million, four hundred ninety-two thousand, nine hundred eighty-seven".