861550 has 12 divisors (see below), whose sum is σ = 1602576. Its totient is φ = 344600.

The previous prime is 861547. The next prime is 861551. The reversal of 861550 is 55168.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861551) 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 5 ways as a sum of consecutive naturals, for example, 8566 + ... + 8665.

It is an arithmetic number, because the mean of its divisors is an integer number (133548).

2⁸⁶¹⁵⁵⁰ is an apocalyptic number.

861550 is a deficient number, since it is larger than the sum of its proper divisors (741026).

861550 is a wasteful number, since it uses less digits than its factorization.

861550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17243 (or 17238 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 25.

The square root of 861550 is about 928.1971773282. The cubic root of 861550 is about 95.1539516725.

The spelling of 861550 in words is "eight hundred sixty-one thousand, five hundred fifty".