861625 has 16 divisors (see below), whose sum is σ = 1102608. Its totient is φ = 672000.

The previous prime is 861617. The next prime is 861647. The reversal of 861625 is 526168.

861625 = 25² + 26² + ... + 137².

It can be written as a sum of positive squares in 8 ways, for example, as 767376 + 94249 = 876^2 + 307^2 .

It is not a de Polignac number, because 861625 - 2³ = 861617 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 861593 and 861602.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 7569 + ... + 7681.

It is an arithmetic number, because the mean of its divisors is an integer number (68913).

2⁸⁶¹⁶²⁵ is an apocalyptic number.

It is an amenable number.

861625 is a deficient number, since it is larger than the sum of its proper divisors (240983).

861625 is a wasteful number, since it uses less digits than its factorization.

861625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189 (or 179 counting only the distinct ones).

The product of its digits is 2880, while the sum is 28.

The square root of 861625 is about 928.2375773475. The cubic root of 861625 is about 95.1567127192.

It can be divided in two parts, 86 and 1625, that added together give a triangular number (1711 = T₅₈).

The spelling of 861625 in words is "eight hundred sixty-one thousand, six hundred twenty-five".