21038418 has 48 divisors (see below), whose sum is σ = 48648600. Its totient is φ = 6547968.

The previous prime is 21038393. The next prime is 21038419. The reversal of 21038418 is 81483012.

21038418 is a `hidden beast` number, since 210 + 38 + 418 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 20223009 + 815409 = 4497^2 + 903^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21038391 and 21038400.

It is not an unprimeable number, because it can be changed into a prime (21038419) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 60108 + ... + 60456.

Almost surely, 2^21038418 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21038418, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24324300).

21038418 is an abundant number, since it is smaller than the sum of its proper divisors (27610182).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21038418 is a wasteful number, since it uses less digits than its factorization.

21038418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 571 (or 568 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 21038418 is about 4586.7655270354. The cubic root of 21038418 is about 276.0605569706.

The spelling of 21038418 in words is "twenty-one million, thirty-eight thousand, four hundred eighteen".