21280748 has 6 divisors (see below), whose sum is σ = 37241316. Its totient is φ = 10640372.

The previous prime is 21280747. The next prime is 21280757. The reversal of 21280748 is 84708212.

It is not an unprimeable number, because it can be changed into a prime (21280747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2660090 + ... + 2660097.

It is an arithmetic number, because the mean of its divisors is an integer number (6206886).

Almost surely, 2^21280748 is an apocalyptic number.

It is an amenable number.

21280748 is a deficient number, since it is larger than the sum of its proper divisors (15960568).

21280748 is a wasteful number, since it uses less digits than its factorization.

21280748 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5320191 (or 5320189 counting only the distinct ones).

The product of its (nonzero) digits is 7168, while the sum is 32.

The square root of 21280748 is about 4613.1061119380. The cubic root of 21280748 is about 277.1164432868.

The spelling of 21280748 in words is "twenty-one million, two hundred eighty thousand, seven hundred forty-eight".