21351422693 has 2 divisors, whose sum is σ = 21351422694. Its totient is φ = 21351422692.

The previous prime is 21351422671. The next prime is 21351422699. The reversal of 21351422693 is 39622415312.

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., 16746171649 + 4605251044 = 129407^2 + 67862^2 .

It is a cyclic number.

It is not a de Polignac number, because 21351422693 - 2²⁰ = 21350374117 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21351422699) 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, 10675711346 + 10675711347.

It is an arithmetic number, because the mean of its divisors is an integer number (10675711347).

Almost surely, 2^21351422693 is an apocalyptic number.

It is an amenable number.

21351422693 is a deficient number, since it is larger than the sum of its proper divisors (1).

21351422693 is an equidigital number, since it uses as much as digits as its factorization.

21351422693 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 38.

The spelling of 21351422693 in words is "twenty-one billion, three hundred fifty-one million, four hundred twenty-two thousand, six hundred ninety-three".