21242080 has 24 divisors (see below), whose sum is σ = 50184792. Its totient is φ = 8496768.

The previous prime is 21242077. The next prime is 21242093. The reversal of 21242080 is 8024212.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66222 + ... + 66541.

It is an arithmetic number, because the mean of its divisors is an integer number (2091033).

Almost surely, 2^21242080 is an apocalyptic number.

21242080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21242080 is an abundant number, since it is smaller than the sum of its proper divisors (28942712).

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

21242080 is a wasteful number, since it uses less digits than its factorization.

21242080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132778 (or 132770 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 21242080 is about 4608.9131039758. The cubic root of 21242080 is about 276.9484975081.

Adding to 21242080 its reverse (8024212), we get a palindrome (29266292).

The spelling of 21242080 in words is "twenty-one million, two hundred forty-two thousand, eighty".