21085944099 has 64 divisors (see below), whose sum is σ = 31874304000. Its totient is φ = 12288568320.

The previous prime is 21085944049. The next prime is 21085944119. The reversal of 21085944099 is 99044958012.

It is a Cunningham number, because it is equal to 145210²-1.

It is not a de Polignac number, because 21085944099 - 2⁸ = 21085943843 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21085944049) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 42256152 + ... + 42256650.

It is an arithmetic number, because the mean of its divisors is an integer number (498036000).

Almost surely, 2^21085944099 is an apocalyptic number.

21085944099 is a deficient number, since it is larger than the sum of its proper divisors (10788359901).

21085944099 is a wasteful number, since it uses less digits than its factorization.

21085944099 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 960.

The product of its (nonzero) digits is 933120, while the sum is 51.

The spelling of 21085944099 in words is "twenty-one billion, eighty-five million, nine hundred forty-four thousand, ninety-nine".