131223221 has 8 divisors (see below), whose sum is σ = 139604544. Its totient is φ = 122915520.

The previous prime is 131223193. The next prime is 131223227. The reversal of 131223221 is 122322131.

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-131223221 is a prime.

It is a super-2 number, since 2×131223221² = 34439067459229682, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a self number, because there is not a number n which added to its sum of digits gives 131223221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131223227) 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, 14705 + ... + 21878.

It is an arithmetic number, because the mean of its divisors is an integer number (17450568).

Almost surely, 2^131223221 is an apocalyptic number.

It is an amenable number.

131223221 is a deficient number, since it is larger than the sum of its proper divisors (8381323).

131223221 is a wasteful number, since it uses less digits than its factorization.

131223221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36811.

The product of its digits is 144, while the sum is 17.

The square root of 131223221 is about 11455.2704463928. The cubic root of 131223221 is about 508.1636134178.

Adding to 131223221 its reverse (122322131), we get a palindrome (253545352).

The spelling of 131223221 in words is "one hundred thirty-one million, two hundred twenty-three thousand, two hundred twenty-one".