21801450449 has 4 divisors (see below), whose sum is σ = 21808403364. Its totient is φ = 21794497536.

The previous prime is 21801450443. The next prime is 21801450469. The reversal of 21801450449 is 94405410812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11067040000 + 10734410449 = 105200^2 + 103607^2 .

It is a cyclic number.

It is not a de Polignac number, because 21801450449 - 2²⁰ = 21800401873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21801450443) 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, 3471752 + ... + 3478025.

It is an arithmetic number, because the mean of its divisors is an integer number (5452100841).

Almost surely, 2^21801450449 is an apocalyptic number.

It is an amenable number.

21801450449 is a deficient number, since it is larger than the sum of its proper divisors (6952915).

21801450449 is an equidigital number, since it uses as much as digits as its factorization.

21801450449 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6952914.

The product of its (nonzero) digits is 46080, while the sum is 38.

The spelling of 21801450449 in words is "twenty-one billion, eight hundred one million, four hundred fifty thousand, four hundred forty-nine".