21231221031011 has 4 divisors (see below), whose sum is σ = 21231588226800. Its totient is φ = 21230853835224.

The previous prime is 21231221030993. The next prime is 21231221031049. The reversal of 21231221031011 is 11013012213212.

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 21231221031011 - 2⁶ = 21231221030947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21231271031011) 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, 183511151 + ... + 183626808.

It is an arithmetic number, because the mean of its divisors is an integer number (5307897056700).

Almost surely, 2^{21231221031011} is an apocalyptic number.

21231221031011 is a deficient number, since it is larger than the sum of its proper divisors (367195789).

21231221031011 is an equidigital number, since it uses as much as digits as its factorization.

21231221031011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 367195788.

The product of its (nonzero) digits is 144, while the sum is 20.

Adding to 21231221031011 its reverse (11013012213212), we get a palindrome (32244233244223).

The spelling of 21231221031011 in words is "twenty-one trillion, two hundred thirty-one billion, two hundred twenty-one million, thirty-one thousand, eleven".