21275519909 has 4 divisors (see below), whose sum is σ = 24314879904. Its totient is φ = 18236159916.

The previous prime is 21275519807. The next prime is 21275519917. The reversal of 21275519909 is 90991557212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21275519909 - 2⁸ = 21275519653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21275519959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1519679987 + ... + 1519680000.

It is an arithmetic number, because the mean of its divisors is an integer number (6078719976).

Almost surely, 2^21275519909 is an apocalyptic number.

It is an amenable number.

21275519909 is a deficient number, since it is larger than the sum of its proper divisors (3039359995).

21275519909 is an equidigital number, since it uses as much as digits as its factorization.

21275519909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3039359994.

The product of its (nonzero) digits is 510300, while the sum is 50.

The spelling of 21275519909 in words is "twenty-one billion, two hundred seventy-five million, five hundred nineteen thousand, nine hundred nine".