861538 has 4 divisors (see below), whose sum is σ = 1292310. Its totient is φ = 430768.

The previous prime is 861499. The next prime is 861541. The reversal of 861538 is 835168.

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

It can be written as a sum of positive squares in only one way, i.e., 859329 + 2209 = 927^2 + 47^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a plaindrome in base 12.

It is an unprimeable number.

861538 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 as a sum of consecutive naturals, namely, 215383 + ... + 215386.

2⁸⁶¹⁵³⁸ is an apocalyptic number.

861538 is a deficient number, since it is larger than the sum of its proper divisors (430772).

861538 is a wasteful number, since it uses less digits than its factorization.

861538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430771.

The product of its digits is 5760, while the sum is 31.

The square root of 861538 is about 928.1907131619. The cubic root of 861538 is about 95.1535098902.

The spelling of 861538 in words is "eight hundred sixty-one thousand, five hundred thirty-eight".