865960821 has 48 divisors (see below), whose sum is σ = 1429845760. Its totient is φ = 517492800.

The previous prime is 865960817. The next prime is 865960831. The reversal of 865960821 is 128069568.

It is not a de Polignac number, because 865960821 - 2² = 865960817 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (865960811) 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 47 ways as a sum of consecutive naturals, for example, 236676 + ... + 240306.

Almost surely, 2^865960821 is an apocalyptic number.

It is an amenable number.

865960821 is a deficient number, since it is larger than the sum of its proper divisors (563884939).

865960821 is a wasteful number, since it uses less digits than its factorization.

865960821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3735 (or 3718 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The square root of 865960821 is about 29427.2122532869. The cubic root of 865960821 is about 953.1605982240.

The spelling of 865960821 in words is "eight hundred sixty-five million, nine hundred sixty thousand, eight hundred twenty-one".