861646 has 4 divisors (see below), whose sum is σ = 1292472. Its totient is φ = 430822.

The previous prime is 861617. The next prime is 861647. The reversal of 861646 is 646168.

It is a semiprime because it is the product of two primes.

It is a plaindrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861647) 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 as a sum of consecutive naturals, namely, 215410 + ... + 215413.

It is an arithmetic number, because the mean of its divisors is an integer number (323118).

2⁸⁶¹⁶⁴⁶ is an apocalyptic number.

861646 is a deficient number, since it is larger than the sum of its proper divisors (430826).

861646 is a wasteful number, since it uses less digits than its factorization.

861646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430825.

The product of its digits is 6912, while the sum is 31.

The square root of 861646 is about 928.2488890378. The cubic root of 861646 is about 95.1574857835.

The spelling of 861646 in words is "eight hundred sixty-one thousand, six hundred forty-six".