21780886808 has 16 divisors (see below), whose sum is σ = 40909949880. Its totient is φ = 10871566848.

The previous prime is 21780886801. The next prime is 21780886871. The reversal of 21780886808 is 80868808712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21780886801) 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 3 ways as a sum of consecutive naturals, for example, 2354666 + ... + 2363897.

Almost surely, 2^21780886808 is an apocalyptic number.

It is an amenable number.

21780886808 is a deficient number, since it is larger than the sum of its proper divisors (19129063072).

21780886808 is a wasteful number, since it uses less digits than its factorization.

21780886808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4719146 (or 4719142 counting only the distinct ones).

The product of its (nonzero) digits is 2752512, while the sum is 56.

The spelling of 21780886808 in words is "twenty-one billion, seven hundred eighty million, eight hundred eighty-six thousand, eight hundred eight".