21147080256 has 336 divisors, whose sum is σ = 68898211200. Its totient is φ = 6165282816.

The previous prime is 21147080243. The next prime is 21147080287. The reversal of 21147080256 is 65208074112.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21147080256.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 7298200 + ... + 7301096.

It is an arithmetic number, because the mean of its divisors is an integer number (205054200).

Almost surely, 2^21147080256 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 21147080256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34449105600).

21147080256 is an abundant number, since it is smaller than the sum of its proper divisors (47751130944).

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

21147080256 is a wasteful number, since it uses less digits than its factorization.

21147080256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2986 (or 2973 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The spelling of 21147080256 in words is "twenty-one billion, one hundred forty-seven million, eighty thousand, two hundred fifty-six".