21009922693 has 2 divisors, whose sum is σ = 21009922694. Its totient is φ = 21009922692.

The previous prime is 21009922691. The next prime is 21009922709. The reversal of 21009922693 is 39622990012.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17402358724 + 3607563969 = 131918^2 + 60063^2 .

It is a cyclic number.

It is not a de Polignac number, because 21009922693 - 2¹ = 21009922691 is a prime.

Together with 21009922691, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21009922691) 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, 10504961346 + 10504961347.

It is an arithmetic number, because the mean of its divisors is an integer number (10504961347).

Almost surely, 2^21009922693 is an apocalyptic number.

It is an amenable number.

21009922693 is a deficient number, since it is larger than the sum of its proper divisors (1).

21009922693 is an equidigital number, since it uses as much as digits as its factorization.

21009922693 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 104976, while the sum is 43.

The spelling of 21009922693 in words is "twenty-one billion, nine million, nine hundred twenty-two thousand, six hundred ninety-three".