21268242 has 18 divisors (see below), whose sum is σ = 46123623. Its totient is φ = 7082892.

The previous prime is 21268231. The next prime is 21268249. The reversal of 21268242 is 24286212.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 10634121 + 10634121 = 3261^2 + 3261^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=3261.

It is not an unprimeable number, because it can be changed into a prime (21268249) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 19023 + ... + 20109.

Almost surely, 2^21268242 is an apocalyptic number.

21268242 is an abundant number, since it is smaller than the sum of its proper divisors (24855381).

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

21268242 is an equidigital number, since it uses as much as digits as its factorization.

21268242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2182 (or 1092 counting only the distinct ones).

The product of its digits is 3072, while the sum is 27.

The square root of 21268242 is about 4611.7504268987. The cubic root of 21268242 is about 277.0621485578.

The spelling of 21268242 in words is "twenty-one million, two hundred sixty-eight thousand, two hundred forty-two".