868821555 has 32 divisors (see below), whose sum is σ = 1622513664. Its totient is φ = 388722816.

The previous prime is 868821553. The next prime is 868821557. The reversal of 868821555 is 555128868.

868821555 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (868821553) and next prime (868821557).

It is not a de Polignac number, because 868821555 - 2¹ = 868821553 is a prime.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (868821553) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 83092 + ... + 92961.

It is an arithmetic number, because the mean of its divisors is an integer number (50703552).

Almost surely, 2^868821555 is an apocalyptic number.

868821555 is a deficient number, since it is larger than the sum of its proper divisors (753692109).

868821555 is a wasteful number, since it uses less digits than its factorization.

868821555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176115.

The product of its digits is 768000, while the sum is 48.

The square root of 868821555 is about 29475.7791245626. The cubic root of 868821555 is about 954.2090451187.

The spelling of 868821555 in words is "eight hundred sixty-eight million, eight hundred twenty-one thousand, five hundred fifty-five".