21120231 has 8 divisors (see below), whose sum is σ = 30720384. Its totient is φ = 12800120.

The previous prime is 21120223. The next prime is 21120251. The reversal of 21120231 is 13202112.

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 21120231 - 2³ = 21120223 is a prime.

It is a super-2 number, since 2×21120231² = 892128314986722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 319971 + ... + 320036.

It is an arithmetic number, because the mean of its divisors is an integer number (3840048).

Almost surely, 2^21120231 is an apocalyptic number.

21120231 is a deficient number, since it is larger than the sum of its proper divisors (9600153).

21120231 is a wasteful number, since it uses less digits than its factorization.

21120231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 640021.

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

The square root of 21120231 is about 4595.6752496233. The cubic root of 21120231 is about 276.4179369668.

Adding to 21120231 its reverse (13202112), we get a palindrome (34322343).

The spelling of 21120231 in words is "twenty-one million, one hundred twenty thousand, two hundred thirty-one".