131223121 has 8 divisors (see below), whose sum is σ = 134001864. Its totient is φ = 128471040.

The previous prime is 131223109. The next prime is 131223149. The reversal of 131223121 is 121322131.

It can be written as a sum of positive squares in 4 ways, for example, as 9363600 + 121859521 = 3060^2 + 11039^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-131223121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 131223095 and 131223104.

It is not an unprimeable number, because it can be changed into a prime (131223181) 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, 3441 + ... + 16561.

It is an arithmetic number, because the mean of its divisors is an integer number (16750233).

Almost surely, 2^131223121 is an apocalyptic number.

It is an amenable number.

131223121 is a deficient number, since it is larger than the sum of its proper divisors (2778743).

131223121 is a wasteful number, since it uses less digits than its factorization.

131223121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13331.

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

The square root of 131223121 is about 11455.2660815889. The cubic root of 131223121 is about 508.1634843340.

Adding to 131223121 its reverse (121322131), we get a palindrome (252545252).

The spelling of 131223121 in words is "one hundred thirty-one million, two hundred twenty-three thousand, one hundred twenty-one".