42861 has 16 divisors (see below), whose sum is σ = 70784. Its totient is φ = 22464.

The previous prime is 42859. The next prime is 42863. The reversal of 42861 is 16824.

Added to its reverse (16824) it gives a triangular number (59685 = T₃₄₅).

It is an interprime number because it is at equal distance from previous prime (42859) and next prime (42863).

It is not a de Polignac number, because 42861 - 2¹ = 42859 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a plaindrome in base 8.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42863) 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, 195 + ... + 351.

It is an arithmetic number, because the mean of its divisors is an integer number (4424).

2⁴²⁸⁶¹ is an apocalyptic number.

It is an amenable number.

42861 is a deficient number, since it is larger than the sum of its proper divisors (27923).

42861 is a wasteful number, since it uses less digits than its factorization.

42861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180.

The product of its digits is 384, while the sum is 21.

The square root of 42861 is about 207.0289834782. The cubic root of 42861 is about 34.9961900615.

Adding to 42861 its reverse (16824), we get a triangular number (59685 = T₃₄₅).

It can be divided in two parts, 42 and 861, that added together give a triangular number (903 = T₄₂).

The spelling of 42861 in words is "forty-two thousand, eight hundred sixty-one".