861975 has 24 divisors (see below), whose sum is σ = 1584720. Its totient is φ = 459360.

The previous prime is 861947. The next prime is 861977. The reversal of 861975 is 579168.

861975 = T₂₅₀ + T₂₅₁ + ... + T₂₇₄.

It is not a de Polignac number, because 861975 - 2⁸ = 861719 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 37 + ... + 1313.

It is an arithmetic number, because the mean of its divisors is an integer number (66030).

2⁸⁶¹⁹⁷⁵ is an apocalyptic number.

861975 is a deficient number, since it is larger than the sum of its proper divisors (722745).

861975 is a wasteful number, since it uses less digits than its factorization.

861975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1296 (or 1285 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 861975 is about 928.4260875266. The cubic root of 861975 is about 95.1695954856.

The spelling of 861975 in words is "eight hundred sixty-one thousand, nine hundred seventy-five".