21540838 has 16 divisors (see below), whose sum is σ = 35323920. Its totient is φ = 9770400.

The previous prime is 21540833. The next prime is 21540847. The reversal of 21540838 is 83804512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21540833) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14908 + ... + 16288.

It is an arithmetic number, because the mean of its divisors is an integer number (2207745).

Almost surely, 2^21540838 is an apocalyptic number.

21540838 is a deficient number, since it is larger than the sum of its proper divisors (13783082).

21540838 is a wasteful number, since it uses less digits than its factorization.

21540838 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2103.

The product of its (nonzero) digits is 7680, while the sum is 31.

The square root of 21540838 is about 4641.2108333925. The cubic root of 21540838 is about 278.2408330037.

The spelling of 21540838 in words is "twenty-one million, five hundred forty thousand, eight hundred thirty-eight".