21800773 has 4 divisors (see below), whose sum is σ = 21823308. Its totient is φ = 21778240.

The previous prime is 21800759. The next prime is 21800777. The reversal of 21800773 is 37700812.

It is a happy number.

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 3678724 + 18122049 = 1918^2 + 4257^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21800773 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21800777) 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, 9748 + ... + 11773.

It is an arithmetic number, because the mean of its divisors is an integer number (5455827).

Almost surely, 2^21800773 is an apocalyptic number.

It is an amenable number.

21800773 is a deficient number, since it is larger than the sum of its proper divisors (22535).

21800773 is a wasteful number, since it uses less digits than its factorization.

21800773 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22534.

The product of its (nonzero) digits is 2352, while the sum is 28.

The square root of 21800773 is about 4669.1297904428. The cubic root of 21800773 is about 279.3555459097.

The spelling of 21800773 in words is "twenty-one million, eight hundred thousand, seven hundred seventy-three".