21099337409 has 2 divisors, whose sum is σ = 21099337410. Its totient is φ = 21099337408.

The previous prime is 21099337393. The next prime is 21099337439. The reversal of 21099337409 is 90473399012.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20535749809 + 563587600 = 143303^2 + 23740^2 .

It is a cyclic number.

It is not a de Polignac number, because 21099337409 - 2⁴ = 21099337393 is a prime.

It is not a weakly prime, because it can be changed into another prime (21099337439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10549668704 + 10549668705.

It is an arithmetic number, because the mean of its divisors is an integer number (10549668705).

Almost surely, 2^21099337409 is an apocalyptic number.

It is an amenable number.

21099337409 is a deficient number, since it is larger than the sum of its proper divisors (1).

21099337409 is an equidigital number, since it uses as much as digits as its factorization.

21099337409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 367416, while the sum is 47.

The spelling of 21099337409 in words is "twenty-one billion, ninety-nine million, three hundred thirty-seven thousand, four hundred nine".