21002136667 has 2 divisors, whose sum is σ = 21002136668. Its totient is φ = 21002136666.

The previous prime is 21002136593. The next prime is 21002136689. The reversal of 21002136667 is 76663120012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21002136667 - 2⁷ = 21002136539 is a prime.

It is not a weakly prime, because it can be changed into another prime (21002133667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501068333 + 10501068334.

It is an arithmetic number, because the mean of its divisors is an integer number (10501068334).

Almost surely, 2^21002136667 is an apocalyptic number.

21002136667 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002136667 is an equidigital number, since it uses as much as digits as its factorization.

21002136667 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18144, while the sum is 34.

Adding to 21002136667 its reverse (76663120012), we get a palindrome (97665256679).

The spelling of 21002136667 in words is "twenty-one billion, two million, one hundred thirty-six thousand, six hundred sixty-seven".