21313242 has 12 divisors (see below), whose sum is σ = 46178730. Its totient is φ = 7104408.

The previous prime is 21313241. The next prime is 21313247. The reversal of 21313242 is 24231312.

It can be written as a sum of positive squares in only one way, i.e., 11634921 + 9678321 = 3411^2 + 3111^2 .

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 1184069 = 21313242 / (2 + 1 + 3 + 1 + 3 + 2 + 4 + 2).

It is not an unprimeable number, because it can be changed into a prime (21313241) 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 5 ways as a sum of consecutive naturals, for example, 592017 + ... + 592052.

Almost surely, 2^21313242 is an apocalyptic number.

21313242 is an abundant number, since it is smaller than the sum of its proper divisors (24865488).

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

21313242 is a wasteful number, since it uses less digits than its factorization.

21313242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1184077 (or 1184074 counting only the distinct ones).

The product of its digits is 288, while the sum is 18.

The square root of 21313242 is about 4616.6266905610. The cubic root of 21313242 is about 277.2574164406.

Adding to 21313242 its reverse (24231312), we get a palindrome (45544554).

The spelling of 21313242 in words is "twenty-one million, three hundred thirteen thousand, two hundred forty-two".