21988978255 has 16 divisors (see below), whose sum is σ = 27813225600. Its totient is φ = 16642726560.

The previous prime is 21988978243. The next prime is 21988978283. The reversal of 21988978255 is 55287988912.

It is not a de Polignac number, because 21988978255 - 2⁵ = 21988978223 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 86401 + ... + 226810.

It is an arithmetic number, because the mean of its divisors is an integer number (1738326600).

Almost surely, 2^21988978255 is an apocalyptic number.

21988978255 is a deficient number, since it is larger than the sum of its proper divisors (5824247345).

21988978255 is a wasteful number, since it uses less digits than its factorization.

21988978255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 313974.

The product of its digits is 29030400, while the sum is 64.

The spelling of 21988978255 in words is "twenty-one billion, nine hundred eighty-eight million, nine hundred seventy-eight thousand, two hundred fifty-five".