21404404493 has 2 divisors, whose sum is σ = 21404404494. Its totient is φ = 21404404492.

The previous prime is 21404404487. The next prime is 21404404543. The reversal of 21404404493 is 39440440412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16280994409 + 5123410084 = 127597^2 + 71578^2 .

It is a cyclic number.

It is not a de Polignac number, because 21404404493 - 2²⁰ = 21403355917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21404404193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10702202246 + 10702202247.

It is an arithmetic number, because the mean of its divisors is an integer number (10702202247).

Almost surely, 2^21404404493 is an apocalyptic number.

It is an amenable number.

21404404493 is a deficient number, since it is larger than the sum of its proper divisors (1).

21404404493 is an equidigital number, since it uses as much as digits as its factorization.

21404404493 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 55296, while the sum is 35.

The spelling of 21404404493 in words is "twenty-one billion, four hundred four million, four hundred four thousand, four hundred ninety-three".