21321924647 has 2 divisors, whose sum is σ = 21321924648. Its totient is φ = 21321924646.

The previous prime is 21321924619. The next prime is 21321924667. The reversal of 21321924647 is 74642912312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21321924647 - 2³² = 17026957351 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21321924667) 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, 10660962323 + 10660962324.

It is an arithmetic number, because the mean of its divisors is an integer number (10660962324).

Almost surely, 2^21321924647 is an apocalyptic number.

21321924647 is a deficient number, since it is larger than the sum of its proper divisors (1).

21321924647 is an equidigital number, since it uses as much as digits as its factorization.

21321924647 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 41.

The spelling of 21321924647 in words is "twenty-one billion, three hundred twenty-one million, nine hundred twenty-four thousand, six hundred forty-seven".