21373528 has 32 divisors (see below), whose sum is σ = 44226000. Its totient is φ = 9602560.

The previous prime is 21373523. The next prime is 21373543. The reversal of 21373528 is 82537312.

It is a self number, because there is not a number n which added to its sum of digits gives 21373528.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21373523) 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, 6468 + ... + 9196.

Almost surely, 2^21373528 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21373528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22113000).

21373528 is an abundant number, since it is smaller than the sum of its proper divisors (22852472).

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

21373528 is a wasteful number, since it uses less digits than its factorization.

21373528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2835 (or 2831 counting only the distinct ones).

The product of its digits is 10080, while the sum is 31.

The square root of 21373528 is about 4623.1513061980. The cubic root of 21373528 is about 277.5185843680.

It can be divided in two parts, 2137 and 3528, that added together give a palindrome (5665).

The spelling of 21373528 in words is "twenty-one million, three hundred seventy-three thousand, five hundred twenty-eight".