21850225 has 6 divisors (see below), whose sum is σ = 27094310. Its totient is φ = 17480160.

The previous prime is 21850193. The next prime is 21850259. The reversal of 21850225 is 52205812.

It can be written as a sum of positive squares in 3 ways, for example, as 2849344 + 19000881 = 1688^2 + 4359^2 .

It is not a de Polignac number, because 21850225 - 2⁵ = 21850193 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25), and also a Moran number because the ratio is a prime number: 874009 = 21850225 / (2 + 1 + 8 + 5 + 0 + 2 + 2 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 21850225.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 436980 + ... + 437029.

Almost surely, 2^21850225 is an apocalyptic number.

21850225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21850225 is a deficient number, since it is larger than the sum of its proper divisors (5244085).

21850225 is an equidigital number, since it uses as much as digits as its factorization.

21850225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 874019 (or 874014 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 25.

The square root of 21850225 is about 4674.4224242146. The cubic root of 21850225 is about 279.5666127074.

The spelling of 21850225 in words is "twenty-one million, eight hundred fifty thousand, two hundred twenty-five".