21159138 has 96 divisors (see below), whose sum is σ = 57341952. Its totient is φ = 5054400.

The previous prime is 21159133. The next prime is 21159161. The reversal of 21159138 is 83195112.

It is not an unprimeable number, because it can be changed into a prime (21159133) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 77943 + ... + 78213.

It is an arithmetic number, because the mean of its divisors is an integer number (597312).

Almost surely, 2^21159138 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21159138, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28670976).

21159138 is an abundant number, since it is smaller than the sum of its proper divisors (36182814).

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

21159138 is a wasteful number, since it uses less digits than its factorization.

21159138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320 (or 307 counting only the distinct ones).

The product of its digits is 2160, while the sum is 30.

The square root of 21159138 is about 4599.9063033936. The cubic root of 21159138 is about 276.5875688789.

The spelling of 21159138 in words is "twenty-one million, one hundred fifty-nine thousand, one hundred thirty-eight".