21133747 has 2 divisors, whose sum is σ = 21133748. Its totient is φ = 21133746.

The previous prime is 21133733. The next prime is 21133753. The reversal of 21133747 is 74733112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21133747 is a prime.

It is not a weakly prime, because it can be changed into another prime (21133727) 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 as a sum of consecutive naturals, namely, 10566873 + 10566874.

It is an arithmetic number, because the mean of its divisors is an integer number (10566874).

Almost surely, 2^21133747 is an apocalyptic number.

21133747 is a deficient number, since it is larger than the sum of its proper divisors (1).

21133747 is an equidigital number, since it uses as much as digits as its factorization.

21133747 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3528, while the sum is 28.

The square root of 21133747 is about 4597.1455273898. The cubic root of 21133747 is about 276.4768894178.

Adding to 21133747 its reverse (74733112), we get a palindrome (95866859).

The spelling of 21133747 in words is "twenty-one million, one hundred thirty-three thousand, seven hundred forty-seven".