21825218 has 8 divisors (see below), whose sum is σ = 33044112. Its totient is φ = 10810516.

The previous prime is 21825217. The next prime is 21825253. The reversal of 21825218 is 81252812.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21825217) 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, 50780 + ... + 51207.

It is an arithmetic number, because the mean of its divisors is an integer number (4130514).

Almost surely, 2^21825218 is an apocalyptic number.

21825218 is a deficient number, since it is larger than the sum of its proper divisors (11218894).

21825218 is a wasteful number, since it uses less digits than its factorization.

21825218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102096.

The product of its digits is 2560, while the sum is 29.

The square root of 21825218 is about 4671.7467825215. The cubic root of 21825218 is about 279.4599198163.

The spelling of 21825218 in words is "twenty-one million, eight hundred twenty-five thousand, two hundred eighteen".