2021888778 has 64 divisors (see below), whose sum is σ = 5269743360. Its totient is φ = 501875712.

The previous prime is 2021888747. The next prime is 2021888779. The reversal of 2021888778 is 8778881202.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a self number, because there is not a number n which added to its sum of digits gives 2021888778.

It is not an unprimeable number, because it can be changed into a prime (2021888779) 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 31 ways as a sum of consecutive naturals, for example, 99633 + ... + 118196.

It is an arithmetic number, because the mean of its divisors is an integer number (82339740).

Almost surely, 2^2021888778 is an apocalyptic number.

2021888778 is an abundant number, since it is smaller than the sum of its proper divisors (3247854582).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2021888778 is a wasteful number, since it uses less digits than its factorization.

2021888778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 217871.

The product of its (nonzero) digits is 802816, while the sum is 51.

The square root of 2021888778 is about 44965.4175784013. The cubic root of 2021888778 is about 1264.5007383700.

The spelling of 2021888778 in words is "two billion, twenty-one million, eight hundred eighty-eight thousand, seven hundred seventy-eight".