21289281760 has 24 divisors (see below), whose sum is σ = 50295928536. Its totient is φ = 8515712640.

The previous prime is 21289281751. The next prime is 21289281763. The reversal of 21289281760 is 6718298212.

It is a self number, because there is not a number n which added to its sum of digits gives 21289281760.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21289281763) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66528846 + ... + 66529165.

It is an arithmetic number, because the mean of its divisors is an integer number (2095663689).

Almost surely, 2^21289281760 is an apocalyptic number.

21289281760 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21289281760 is an abundant number, since it is smaller than the sum of its proper divisors (29006646776).

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

21289281760 is a wasteful number, since it uses less digits than its factorization.

21289281760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133058026 (or 133058018 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 46.

The spelling of 21289281760 in words is "twenty-one billion, two hundred eighty-nine million, two hundred eighty-one thousand, seven hundred sixty".