131221111 has 8 divisors (see below), whose sum is σ = 150679424. Its totient is φ = 111940920.

The previous prime is 131221093. The next prime is 131221117. The reversal of 131221111 is 111122131.

It is a happy number.

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

It is not a de Polignac number, because 131221111 - 2⁷ = 131220983 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 131221091 and 131221100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131221117) 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, 42945 + ... + 45898.

It is an arithmetic number, because the mean of its divisors is an integer number (18834928).

Almost surely, 2^131221111 is an apocalyptic number.

131221111 is a deficient number, since it is larger than the sum of its proper divisors (19458313).

131221111 is an equidigital number, since it uses as much as digits as its factorization.

131221111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89061.

The product of its digits is 12, while the sum is 13.

The square root of 131221111 is about 11455.1783486771. The cubic root of 131221111 is about 508.1608897358.

Adding to 131221111 its reverse (111122131), we get a palindrome (242343242).

The spelling of 131221111 in words is "one hundred thirty-one million, two hundred twenty-one thousand, one hundred eleven".