21280722 has 64 divisors (see below), whose sum is σ = 47779200. Its totient is φ = 6289920.

The previous prime is 21280711. The next prime is 21280729. The reversal of 21280722 is 22708212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21280692 and 21280701.

It is not an unprimeable number, because it can be changed into a prime (21280729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 135468 + ... + 135624.

It is an arithmetic number, because the mean of its divisors is an integer number (746550).

Almost surely, 2^21280722 is an apocalyptic number.

21280722 is an abundant number, since it is smaller than the sum of its proper divisors (26498478).

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

21280722 is a wasteful number, since it uses less digits than its factorization.

21280722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251.

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 21280722 is about 4613.1032938793. The cubic root of 21280722 is about 277.1163304300.

Adding to 21280722 its reverse (22708212), we get a palindrome (43988934).

The spelling of 21280722 in words is "twenty-one million, two hundred eighty thousand, seven hundred twenty-two".