21242106 has 12 divisors (see below), whose sum is σ = 46024602. Its totient is φ = 7080696.

The previous prime is 21242101. The next prime is 21242131. The reversal of 21242106 is 60124212.

It can be written as a sum of positive squares in only one way, i.e., 13068225 + 8173881 = 3615^2 + 2859^2 .

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: 1180117 = 21242106 / (2 + 1 + 2 + 4 + 2 + 1 + 0 + 6).

It is not an unprimeable number, because it can be changed into a prime (21242101) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 590041 + ... + 590076.

Almost surely, 2^21242106 is an apocalyptic number.

21242106 is an abundant number, since it is smaller than the sum of its proper divisors (24782496).

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

21242106 is a wasteful number, since it uses less digits than its factorization.

21242106 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1180125 (or 1180122 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21242106 is about 4608.9159245966. The cubic root of 21242106 is about 276.9486105017.

Adding to 21242106 its reverse (60124212), we get a palindrome (81366318).

The spelling of 21242106 in words is "twenty-one million, two hundred forty-two thousand, one hundred six".