21242002 has 4 divisors (see below), whose sum is σ = 31863006. Its totient is φ = 10621000.

The previous prime is 21241991. The next prime is 21242047. The reversal of 21242002 is 20024212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 19989841 + 1252161 = 4471^2 + 1119^2 .

It is a Smith number, since the sum of its digits (13) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax 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 as a sum of consecutive naturals, namely, 5310499 + ... + 5310502.

Almost surely, 2^21242002 is an apocalyptic number.

21242002 is a deficient number, since it is larger than the sum of its proper divisors (10621004).

21242002 is a wasteful number, since it uses less digits than its factorization.

21242002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10621003.

The product of its (nonzero) digits is 64, while the sum is 13.

The square root of 21242002 is about 4608.9046421032. The cubic root of 21242002 is about 276.9481585267.

Adding to 21242002 its reverse (20024212), we get a palindrome (41266214).

The spelling of 21242002 in words is "twenty-one million, two hundred forty-two thousand, two".