21094431209 has 16 divisors (see below), whose sum is σ = 22475232000. Its totient is φ = 19756678656.

The previous prime is 21094431187. The next prime is 21094431221. The reversal of 21094431209 is 90213449012.

It is a cyclic number.

It is not a de Polignac number, because 21094431209 - 2²⁰ = 21093382633 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21094431229) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 160817 + ... + 260865.

It is an arithmetic number, because the mean of its divisors is an integer number (1404702000).

Almost surely, 2^21094431209 is an apocalyptic number.

It is an amenable number.

21094431209 is a deficient number, since it is larger than the sum of its proper divisors (1380800791).

21094431209 is a wasteful number, since it uses less digits than its factorization.

21094431209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100264.

The product of its (nonzero) digits is 15552, while the sum is 35.

The spelling of 21094431209 in words is "twenty-one billion, ninety-four million, four hundred thirty-one thousand, two hundred nine".