21800002073 has 4 divisors (see below), whose sum is σ = 21910662180. Its totient is φ = 21689341968.

The previous prime is 21800002039. The next prime is 21800002087. The reversal of 21800002073 is 37020000812.

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 21518836249 + 281165824 = 146693^2 + 16768^2 .

It is a cyclic number.

It is not a de Polignac number, because 21800002073 - 2⁶ = 21800002009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21800002573) 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, 55329758 + ... + 55330151.

It is an arithmetic number, because the mean of its divisors is an integer number (5477665545).

Almost surely, 2^21800002073 is an apocalyptic number.

It is an amenable number.

21800002073 is a deficient number, since it is larger than the sum of its proper divisors (110660107).

21800002073 is a wasteful number, since it uses less digits than its factorization.

21800002073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110660106.

The product of its (nonzero) digits is 672, while the sum is 23.

Adding to 21800002073 its reverse (37020000812), we get a palindrome (58820002885).

The spelling of 21800002073 in words is "twenty-one billion, eight hundred million, two thousand, seventy-three".