21121120331 has 4 divisors (see below), whose sum is σ = 22363539192. Its totient is φ = 19878701472.

The previous prime is 21121120289. The next prime is 21121120403. The reversal of 21121120331 is 13302112112.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21121120331 is a prime.

It is a super-2 number, since 2×21121120331² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 1242418843 = 21121120331 / (2 + 1 + 1 + 2 + 1 + 1 + 2 + 0 + 3 + 3 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21121129331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 621209405 + ... + 621209438.

It is an arithmetic number, because the mean of its divisors is an integer number (5590884798).

Almost surely, 2^21121120331 is an apocalyptic number.

21121120331 is a deficient number, since it is larger than the sum of its proper divisors (1242418861).

21121120331 is a wasteful number, since it uses less digits than its factorization.

21121120331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1242418860.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21121120331 its reverse (13302112112), we get a palindrome (34423232443).

The spelling of 21121120331 in words is "twenty-one billion, one hundred twenty-one million, one hundred twenty thousand, three hundred thirty-one".