21120505 has 8 divisors (see below), whose sum is σ = 28965312. Its totient is φ = 14482608.

The previous prime is 21120503. The next prime is 21120523. The reversal of 21120505 is 50502112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21120505 - 2¹ = 21120503 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21120503) 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, 301687 + ... + 301756.

It is an arithmetic number, because the mean of its divisors is an integer number (3620664).

Almost surely, 2^21120505 is an apocalyptic number.

It is an amenable number.

21120505 is a deficient number, since it is larger than the sum of its proper divisors (7844807).

21120505 is an equidigital number, since it uses as much as digits as its factorization.

21120505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 603455.

The product of its (nonzero) digits is 100, while the sum is 16.

The square root of 21120505 is about 4595.7050601622. The cubic root of 21120505 is about 276.4191323166.

Adding to 21120505 its reverse (50502112), we get a palindrome (71622617).

The spelling of 21120505 in words is "twenty-one million, one hundred twenty thousand, five hundred five".