865941021 has 12 divisors (see below), whose sum is σ = 1364513280. Its totient is φ = 524812680.

The previous prime is 865941001. The next prime is 865941023. The reversal of 865941021 is 120149568.

It is not a de Polignac number, because 865941021 - 2⁵ = 865940989 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (865941023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4373341 + ... + 4373538.

It is an arithmetic number, because the mean of its divisors is an integer number (113709440).

Almost surely, 2^865941021 is an apocalyptic number.

It is an amenable number.

865941021 is a deficient number, since it is larger than the sum of its proper divisors (498572259).

865941021 is a wasteful number, since it uses less digits than its factorization.

865941021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8746896 (or 8746893 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 865941021 is about 29426.8758280589. The cubic root of 865941021 is about 953.1533335675.

The spelling of 865941021 in words is "eight hundred sixty-five million, nine hundred forty-one thousand, twenty-one".