21800345 has 24 divisors (see below), whose sum is σ = 30767688. Its totient is φ = 14784000.

The previous prime is 21800329. The next prime is 21800351. The reversal of 21800345 is 54300812.

It can be written as a sum of positive squares in 4 ways, for example, as 3924361 + 17875984 = 1981^2 + 4228^2 .

It is not a de Polignac number, because 21800345 - 2⁴ = 21800329 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21800345.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24305 + ... + 25185.

It is an arithmetic number, because the mean of its divisors is an integer number (1281987).

Almost surely, 2^21800345 is an apocalyptic number.

It is an amenable number.

21800345 is a deficient number, since it is larger than the sum of its proper divisors (8967343).

21800345 is a wasteful number, since it uses less digits than its factorization.

21800345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1001 (or 994 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 21800345 is about 4669.0839572661. The cubic root of 21800345 is about 279.3537177641.

The spelling of 21800345 in words is "twenty-one million, eight hundred thousand, three hundred forty-five".