21435667493 has 2 divisors, whose sum is σ = 21435667494. Its totient is φ = 21435667492.

The previous prime is 21435667483. The next prime is 21435667501. The reversal of 21435667493 is 39476653412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20113763329 + 1321904164 = 141823^2 + 36358^2 .

It is a cyclic number.

It is not a de Polignac number, because 21435667493 - 2⁸ = 21435667237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21435667483) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10717833746 + 10717833747.

It is an arithmetic number, because the mean of its divisors is an integer number (10717833747).

Almost surely, 2^21435667493 is an apocalyptic number.

It is an amenable number.

21435667493 is a deficient number, since it is larger than the sum of its proper divisors (1).

21435667493 is an equidigital number, since it uses as much as digits as its factorization.

21435667493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3265920, while the sum is 50.

The spelling of 21435667493 in words is "twenty-one billion, four hundred thirty-five million, six hundred sixty-seven thousand, four hundred ninety-three".