21120321031 has 4 divisors (see below), whose sum is σ = 21466555864. Its totient is φ = 20774086200.

The previous prime is 21120321023. The next prime is 21120321071. The reversal of 21120321031 is 13012302112.

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 21120321031 - 2³ = 21120321023 is a prime.

It is a super-2 number, since 2×21120321031² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21120320996 and 21120321014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120321071) 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, 173117325 + ... + 173117446.

It is an arithmetic number, because the mean of its divisors is an integer number (5366638966).

Almost surely, 2^21120321031 is an apocalyptic number.

21120321031 is a deficient number, since it is larger than the sum of its proper divisors (346234833).

21120321031 is an equidigital number, since it uses as much as digits as its factorization.

21120321031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 346234832.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21120321031 its reverse (13012302112), we get a palindrome (34132623143).

The spelling of 21120321031 in words is "twenty-one billion, one hundred twenty million, three hundred twenty-one thousand, thirty-one".