21042438 has 16 divisors (see below), whose sum is σ = 42775536. Its totient is φ = 6899040.

The previous prime is 21042419. The next prime is 21042449. The reversal of 21042438 is 83424012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28381 + ... + 29112.

It is an arithmetic number, because the mean of its divisors is an integer number (2673471).

Almost surely, 2^21042438 is an apocalyptic number.

21042438 is an abundant number, since it is smaller than the sum of its proper divisors (21733098).

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

21042438 is a wasteful number, since it uses less digits than its factorization.

21042438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57559.

The product of its (nonzero) digits is 1536, while the sum is 24.

The square root of 21042438 is about 4587.2037234027. The cubic root of 21042438 is about 276.0781389764.

The spelling of 21042438 in words is "twenty-one million, forty-two thousand, four hundred thirty-eight".