863981 has 4 divisors (see below), whose sum is σ = 870912. Its totient is φ = 857052.

The previous prime is 863959. The next prime is 863983. The reversal of 863981 is 189368.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 863981 - 2⁶ = 863917 is a prime.

It is a super-2 number, since 2×863981² = 1492926336722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (863983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3275 + ... + 3528.

It is an arithmetic number, because the mean of its divisors is an integer number (217728).

2⁸⁶³⁹⁸¹ is an apocalyptic number.

It is an amenable number.

863981 is a deficient number, since it is larger than the sum of its proper divisors (6931).

863981 is a wasteful number, since it uses less digits than its factorization.

863981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6930.

The product of its digits is 10368, while the sum is 35.

The square root of 863981 is about 929.5057826609. The cubic root of 863981 is about 95.2433649505.

The spelling of 863981 in words is "eight hundred sixty-three thousand, nine hundred eighty-one".