21911303909 has 4 divisors (see below), whose sum is σ = 23903240640. Its totient is φ = 19919367180.

The previous prime is 21911303863. The next prime is 21911303917. The reversal of 21911303909 is 90930311912.

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 21911303909 - 2⁸ = 21911303653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21911303959) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 995968349 + ... + 995968370.

It is an arithmetic number, because the mean of its divisors is an integer number (5975810160).

Almost surely, 2^21911303909 is an apocalyptic number.

It is an amenable number.

21911303909 is a deficient number, since it is larger than the sum of its proper divisors (1991936731).

21911303909 is a wasteful number, since it uses less digits than its factorization.

21911303909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1991936730.

The product of its (nonzero) digits is 13122, while the sum is 38.

The spelling of 21911303909 in words is "twenty-one billion, nine hundred eleven million, three hundred three thousand, nine hundred nine".