21246747 has 4 divisors (see below), whose sum is σ = 28329000. Its totient is φ = 14164496.

The previous prime is 21246721. The next prime is 21246751. The reversal of 21246747 is 74764212.

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

It is a cyclic number.

It is not a de Polignac number, because 21246747 - 2⁶ = 21246683 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21246707) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3541122 + ... + 3541127.

It is an arithmetic number, because the mean of its divisors is an integer number (7082250).

Almost surely, 2^21246747 is an apocalyptic number.

21246747 is a deficient number, since it is larger than the sum of its proper divisors (7082253).

21246747 is an equidigital number, since it uses as much as digits as its factorization.

21246747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7082252.

The product of its digits is 18816, while the sum is 33.

The square root of 21246747 is about 4609.4193777525. The cubic root of 21246747 is about 276.9687783844.

The spelling of 21246747 in words is "twenty-one million, two hundred forty-six thousand, seven hundred forty-seven".