21280320744 has 32 divisors (see below), whose sum is σ = 53249809920. Its totient is φ = 7086905856.

The previous prime is 21280320689. The next prime is 21280320757. The reversal of 21280320744 is 44702308212.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 381769 + ... + 433944.

It is an arithmetic number, because the mean of its divisors is an integer number (1664056560).

Almost surely, 2^21280320744 is an apocalyptic number.

21280320744 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21280320744 is an abundant number, since it is smaller than the sum of its proper divisors (31969489176).

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

21280320744 is a wasteful number, since it uses less digits than its factorization.

21280320744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 816809 (or 816805 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 33.

Adding to 21280320744 its reverse (44702308212), we get a palindrome (65982628956).

The spelling of 21280320744 in words is "twenty-one billion, two hundred eighty million, three hundred twenty thousand, seven hundred forty-four".