21520327 has 4 divisors (see below), whose sum is σ = 21815200. Its totient is φ = 21225456.

The previous prime is 21520307. The next prime is 21520361. The reversal of 21520327 is 72302512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21520327 - 2²³ = 13131719 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21520298 and 21520307.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21520307) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 147327 + ... + 147472.

It is an arithmetic number, because the mean of its divisors is an integer number (5453800).

Almost surely, 2^21520327 is an apocalyptic number.

21520327 is a deficient number, since it is larger than the sum of its proper divisors (294873).

21520327 is an equidigital number, since it uses as much as digits as its factorization.

21520327 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 294872.

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 21520327 is about 4639.0006466911. Note that the first 3 decimals coincide. The cubic root of 21520327 is about 278.1524921189.

Adding to 21520327 its reverse (72302512), we get a palindrome (93822839).

The spelling of 21520327 in words is "twenty-one million, five hundred twenty thousand, three hundred twenty-seven".