21271441209 has 4 divisors (see below), whose sum is σ = 28361921616. Its totient is φ = 14180960804.

The previous prime is 21271441207. The next prime is 21271441231. The reversal of 21271441209 is 90214417212.

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 21271441209 - 2¹ = 21271441207 is a prime.

It is a super-2 number, since 2×21271441209² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21271441209.

It is not an unprimeable number, because it can be changed into a prime (21271441207) 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, 3545240199 + ... + 3545240204.

It is an arithmetic number, because the mean of its divisors is an integer number (7090480404).

Almost surely, 2^21271441209 is an apocalyptic number.

It is an amenable number.

21271441209 is a deficient number, since it is larger than the sum of its proper divisors (7090480407).

21271441209 is an equidigital number, since it uses as much as digits as its factorization.

21271441209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7090480406.

The product of its (nonzero) digits is 8064, while the sum is 33.

The spelling of 21271441209 in words is "twenty-one billion, two hundred seventy-one million, four hundred forty-one thousand, two hundred nine".