861381 has 16 divisors (see below), whose sum is σ = 1299520. Its totient is φ = 563760.

The previous prime is 861361. The next prime is 861391. The reversal of 861381 is 183168.

It is not a de Polignac number, because 861381 - 2⁶ = 861317 is a prime.

It is a super-2 number, since 2×861381² = 1483954454322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

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 861381.

It is not an unprimeable number, because it can be changed into a prime (861361) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1386 + ... + 1908.

It is an arithmetic number, because the mean of its divisors is an integer number (81220).

2⁸⁶¹³⁸¹ is an apocalyptic number.

It is an amenable number.

861381 is a deficient number, since it is larger than the sum of its proper divisors (438139).

861381 is a wasteful number, since it uses less digits than its factorization.

861381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 593 (or 587 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 861381 is about 928.1061361719. The cubic root of 861381 is about 95.1477295266.

The spelling of 861381 in words is "eight hundred sixty-one thousand, three hundred eighty-one".