21203570809 has 16 divisors (see below), whose sum is σ = 23305651200. Its totient is φ = 19201278096.

The previous prime is 21203570767. The next prime is 21203570821. The reversal of 21203570809 is 90807530212.

It is a de Polignac number, because none of the positive numbers 2^k-21203570809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21203577809) 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, 665722 + ... + 696844.

It is an arithmetic number, because the mean of its divisors is an integer number (1456603200).

Almost surely, 2^21203570809 is an apocalyptic number.

It is an amenable number.

21203570809 is a deficient number, since it is larger than the sum of its proper divisors (2102080391).

21203570809 is a wasteful number, since it uses less digits than its factorization.

21203570809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32724.

The product of its (nonzero) digits is 30240, while the sum is 37.

The spelling of 21203570809 in words is "twenty-one billion, two hundred three million, five hundred seventy thousand, eight hundred nine".