21872630809 has 4 divisors (see below), whose sum is σ = 21911900004. Its totient is φ = 21833361616.

The previous prime is 21872630789. The next prime is 21872630839. The reversal of 21872630809 is 90803627812.

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 8275904784 + 13596726025 = 90972^2 + 116605^2 .

It is a cyclic number.

It is not a de Polignac number, because 21872630809 - 2¹⁹ = 21872106521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21872630839) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19633762 + ... + 19634875.

It is an arithmetic number, because the mean of its divisors is an integer number (5477975001).

Almost surely, 2^21872630809 is an apocalyptic number.

It is an amenable number.

21872630809 is a deficient number, since it is larger than the sum of its proper divisors (39269195).

21872630809 is an equidigital number, since it uses as much as digits as its factorization.

21872630809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39269194.

The product of its (nonzero) digits is 290304, while the sum is 46.

The spelling of 21872630809 in words is "twenty-one billion, eight hundred seventy-two million, six hundred thirty thousand, eight hundred nine".