21751404247 has 2 divisors, whose sum is σ = 21751404248. Its totient is φ = 21751404246.

The previous prime is 21751404197. The next prime is 21751404263. The reversal of 21751404247 is 74240415712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21751404247 - 2¹⁵ = 21751371479 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21751404287) 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, 10875702123 + 10875702124.

It is an arithmetic number, because the mean of its divisors is an integer number (10875702124).

Almost surely, 2^21751404247 is an apocalyptic number.

21751404247 is a deficient number, since it is larger than the sum of its proper divisors (1).

21751404247 is an equidigital number, since it uses as much as digits as its factorization.

21751404247 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62720, while the sum is 37.

Adding to 21751404247 its reverse (74240415712), we get a palindrome (95991819959).

The spelling of 21751404247 in words is "twenty-one billion, seven hundred fifty-one million, four hundred four thousand, two hundred forty-seven".