861630 has 64 divisors (see below), whose sum is σ = 2585088. Its totient is φ = 178560.

The previous prime is 861617. The next prime is 861647. The reversal of 861630 is 36168.

It is a self number, because there is not a number n which added to its sum of digits gives 861630.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 861630.

It is an unprimeable number.

861630 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2124 + ... + 2496.

It is an arithmetic number, because the mean of its divisors is an integer number (40392).

2⁸⁶¹⁶³⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 861630, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1292544).

861630 is an abundant number, since it is smaller than the sum of its proper divisors (1723458).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

861630 is a wasteful number, since it uses less digits than its factorization.

861630 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 401.

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 861630 is about 928.2402706196. The cubic root of 861630 is about 95.1568967833.

Adding to 861630 its reverse (36168), we get a palindrome (897798).

It can be divided in two parts, 8616 and 30, that added together give a triangular number (8646 = T₁₃₁).

The spelling of 861630 in words is "eight hundred sixty-one thousand, six hundred thirty".