21280452 has 12 divisors (see below), whose sum is σ = 49654416. Its totient is φ = 7093480.

The previous prime is 21280433. The next prime is 21280459. The reversal of 21280452 is 25408212.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (21280459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 886674 + ... + 886697.

It is an arithmetic number, because the mean of its divisors is an integer number (4137868).

Almost surely, 2^21280452 is an apocalyptic number.

It is an amenable number.

21280452 is an abundant number, since it is smaller than the sum of its proper divisors (28373964).

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

21280452 is a wasteful number, since it uses less digits than its factorization.

21280452 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1773378 (or 1773376 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 21280452 is about 4613.0740293214. The cubic root of 21280452 is about 277.1151584503.

Adding to 21280452 its reverse (25408212), we get a palindrome (46688664).

The spelling of 21280452 in words is "twenty-one million, two hundred eighty thousand, four hundred fifty-two".