21404534993 has 2 divisors, whose sum is σ = 21404534994. Its totient is φ = 21404534992.

The previous prime is 21404534941. The next prime is 21404535013. The reversal of 21404534993 is 39943540412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21335860624 + 68674369 = 146068^2 + 8287^2 .

It is a cyclic number.

It is not a de Polignac number, because 21404534993 - 2⁸ = 21404534737 is a prime.

It is not a weakly prime, because it can be changed into another prime (21404534903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10702267496 + 10702267497.

It is an arithmetic number, because the mean of its divisors is an integer number (10702267497).

Almost surely, 2^21404534993 is an apocalyptic number.

It is an amenable number.

21404534993 is a deficient number, since it is larger than the sum of its proper divisors (1).

21404534993 is an equidigital number, since it uses as much as digits as its factorization.

21404534993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 466560, while the sum is 44.

The spelling of 21404534993 in words is "twenty-one billion, four hundred four million, five hundred thirty-four thousand, nine hundred ninety-three".