21278634288 has 80 divisors (see below), whose sum is σ = 56724036096. Its totient is φ = 6868350720.

The previous prime is 21278634277. The next prime is 21278634317. The reversal of 21278634288 is 88243687212.

It is a self number, because there is not a number n which added to its sum of digits gives 21278634288.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 346345 + ... + 403127.

Almost surely, 2^21278634288 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21278634288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28362018048).

21278634288 is an abundant number, since it is smaller than the sum of its proper divisors (35445401808).

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

21278634288 is a wasteful number, since it uses less digits than its factorization.

21278634288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57042 (or 57036 counting only the distinct ones).

The product of its digits is 2064384, while the sum is 51.

The spelling of 21278634288 in words is "twenty-one billion, two hundred seventy-eight million, six hundred thirty-four thousand, two hundred eighty-eight".