21529105993 has 2 divisors, whose sum is σ = 21529105994. Its totient is φ = 21529105992.

The previous prime is 21529105981. The next prime is 21529106003. The reversal of 21529105993 is 39950192512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21529105984 + 9 = 146728^2 + 3^2 .

It is a cyclic number.

It is not a de Polignac number, because 21529105993 - 2²⁹ = 20992235081 is a prime.

It is not a weakly prime, because it can be changed into another prime (21529105933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10764552996 + 10764552997.

It is an arithmetic number, because the mean of its divisors is an integer number (10764552997).

Almost surely, 2^21529105993 is an apocalyptic number.

It is an amenable number.

21529105993 is a deficient number, since it is larger than the sum of its proper divisors (1).

21529105993 is an equidigital number, since it uses as much as digits as its factorization.

21529105993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 218700, while the sum is 46.

The spelling of 21529105993 in words is "twenty-one billion, five hundred twenty-nine million, one hundred five thousand, nine hundred ninety-three".