865555641 has 12 divisors (see below), whose sum is σ = 1259243440. Its totient is φ = 572884920.

The previous prime is 865555631. The next prime is 865555661. The reversal of 865555641 is 146555568.

865555641 is a `hidden beast` number, since 8 + 6 + 55 + 556 + 41 = 666.

It is not a de Polignac number, because 865555641 - 2⁵ = 865555609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (865555631) 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, 344695 + ... + 347196.

Almost surely, 2^865555641 is an apocalyptic number.

It is an amenable number.

865555641 is a deficient number, since it is larger than the sum of its proper divisors (393687799).

865555641 is a wasteful number, since it uses less digits than its factorization.

865555641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 692036 (or 692033 counting only the distinct ones).

The product of its digits is 720000, while the sum is 45.

The square root of 865555641 is about 29420.3270036212. The cubic root of 865555641 is about 953.0119148765.

The spelling of 865555641 in words is "eight hundred sixty-five million, five hundred fifty-five thousand, six hundred forty-one".