21140024021 has 2 divisors, whose sum is σ = 21140024022. Its totient is φ = 21140024020.

The previous prime is 21140023913. The next prime is 21140024023. The reversal of 21140024021 is 12042004112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14625274225 + 6514749796 = 120935^2 + 80714^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21140024021 is a prime.

It is a Sophie Germain prime.

Together with 21140024023, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21140024023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10570012010 + 10570012011.

It is an arithmetic number, because the mean of its divisors is an integer number (10570012011).

Almost surely, 2^21140024021 is an apocalyptic number.

It is an amenable number.

21140024021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21140024021 is an equidigital number, since it uses as much as digits as its factorization.

21140024021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21140024021 its reverse (12042004112), we get a palindrome (33182028133).

The spelling of 21140024021 in words is "twenty-one billion, one hundred forty million, twenty-four thousand, twenty-one".