21335634673 has 2 divisors, whose sum is σ = 21335634674. Its totient is φ = 21335634672.

The previous prime is 21335634613. The next prime is 21335634701. The reversal of 21335634673 is 37643653312.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13223390049 + 8112244624 = 114993^2 + 90068^2 .

It is a cyclic number.

It is not a de Polignac number, because 21335634673 - 2¹⁷ = 21335503601 is a prime.

It is not a weakly prime, because it can be changed into another prime (21335634613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10667817336 + 10667817337.

It is an arithmetic number, because the mean of its divisors is an integer number (10667817337).

Almost surely, 2^21335634673 is an apocalyptic number.

It is an amenable number.

21335634673 is a deficient number, since it is larger than the sum of its proper divisors (1).

21335634673 is an equidigital number, since it uses as much as digits as its factorization.

21335634673 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 816480, while the sum is 43.

The spelling of 21335634673 in words is "twenty-one billion, three hundred thirty-five million, six hundred thirty-four thousand, six hundred seventy-three".