861904 has 20 divisors (see below), whose sum is σ = 1689376. Its totient is φ = 425952.

The previous prime is 861901. The next prime is 861907. The reversal of 861904 is 409168.

861904 = T₁₆₅ + T₁₆₆ + ... + T₂₁₂.

It is an interprime number because it is at equal distance from previous prime (861901) and next prime (861907).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1387 + ... + 1909.

2⁸⁶¹⁹⁰⁴ is an apocalyptic number.

It is an amenable number.

861904 is a deficient number, since it is larger than the sum of its proper divisors (827472).

861904 is a wasteful number, since it uses less digits than its factorization.

861904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 634 (or 628 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 861904 is about 928.3878499851. The cubic root of 861904 is about 95.1669824064.

The spelling of 861904 in words is "eight hundred sixty-one thousand, nine hundred four".