21242426 has 4 divisors (see below), whose sum is σ = 31863642. Its totient is φ = 10621212.

The previous prime is 21242393. The next prime is 21242443. The reversal of 21242426 is 62424212.

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., 11909401 + 9333025 = 3451^2 + 3055^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5310605 + ... + 5310608.

Almost surely, 2^21242426 is an apocalyptic number.

21242426 is a deficient number, since it is larger than the sum of its proper divisors (10621216).

21242426 is a wasteful number, since it uses less digits than its factorization.

21242426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10621215.

The product of its digits is 1536, while the sum is 23.

The square root of 21242426 is about 4608.9506397878. The cubic root of 21242426 is about 276.9500011848.

Adding to 21242426 its reverse (62424212), we get a palindrome (83666638).

The spelling of 21242426 in words is "twenty-one million, two hundred forty-two thousand, four hundred twenty-six".