21242684867 has 2 divisors, whose sum is σ = 21242684868. Its totient is φ = 21242684866.

The previous prime is 21242684863. The next prime is 21242684887. The reversal of 21242684867 is 76848624212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21242684867 - 2² = 21242684863 is a prime.

It is not a weakly prime, because it can be changed into another prime (21242684863) 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, 10621342433 + 10621342434.

It is an arithmetic number, because the mean of its divisors is an integer number (10621342434).

Almost surely, 2^21242684867 is an apocalyptic number.

21242684867 is a deficient number, since it is larger than the sum of its proper divisors (1).

21242684867 is an equidigital number, since it uses as much as digits as its factorization.

21242684867 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2064384, while the sum is 50.

The spelling of 21242684867 in words is "twenty-one billion, two hundred forty-two million, six hundred eighty-four thousand, eight hundred sixty-seven".