21818452 has 6 divisors (see below), whose sum is σ = 38182298. Its totient is φ = 10909224.

The previous prime is 21818449. The next prime is 21818471. The reversal of 21818452 is 25481812.

It can be written as a sum of positive squares in only one way, i.e., 14167696 + 7650756 = 3764^2 + 2766^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2727303 + ... + 2727310.

Almost surely, 2^21818452 is an apocalyptic number.

It is an amenable number.

21818452 is a deficient number, since it is larger than the sum of its proper divisors (16363846).

21818452 is a wasteful number, since it uses less digits than its factorization.

21818452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5454617 (or 5454615 counting only the distinct ones).

The product of its digits is 5120, while the sum is 31.

The square root of 21818452 is about 4671.0225861154. The cubic root of 21818452 is about 279.4310385279.

The spelling of 21818452 in words is "twenty-one million, eight hundred eighteen thousand, four hundred fifty-two".