21120321 has 8 divisors (see below), whose sum is σ = 28252224. Its totient is φ = 14034320.

The previous prime is 21120317. The next prime is 21120349. The reversal of 21120321 is 12302112.

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

It is a cyclic number.

It is not a de Polignac number, because 21120321 - 2² = 21120317 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21120297 and 21120306.

It is not an unprimeable number, because it can be changed into a prime (21120311) 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, 10386 + ... + 12251.

It is an arithmetic number, because the mean of its divisors is an integer number (3531528).

Almost surely, 2^21120321 is an apocalyptic number.

It is an amenable number.

21120321 is a deficient number, since it is larger than the sum of its proper divisors (7131903).

21120321 is a wasteful number, since it uses less digits than its factorization.

21120321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22951.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 21120321 is about 4595.6850414274. The cubic root of 21120321 is about 276.4183296011.

Adding to 21120321 its reverse (12302112), we get a palindrome (33422433).

The spelling of 21120321 in words is "twenty-one million, one hundred twenty thousand, three hundred twenty-one".