131221321 has 32 divisors (see below), whose sum is σ = 169205760. Its totient is φ = 98808000.

The previous prime is 131221313. The next prime is 131221327. The reversal of 131221321 is 123122131.

It is a cyclic number.

It is not a de Polignac number, because 131221321 - 2³ = 131221313 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 131221295 and 131221304.

It is not an unprimeable number, because it can be changed into a prime (131221327) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 365340 + ... + 365698.

It is an arithmetic number, because the mean of its divisors is an integer number (5287680).

Almost surely, 2^131221321 is an apocalyptic number.

131221321 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

131221321 is a deficient number, since it is larger than the sum of its proper divisors (37984439).

131221321 is a wasteful number, since it uses less digits than its factorization.

131221321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 525.

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

The square root of 131221321 is about 11455.1875148336. The cubic root of 131221321 is about 508.1611608144.

Adding to 131221321 its reverse (123122131), we get a palindrome (254343452).

The spelling of 131221321 in words is "one hundred thirty-one million, two hundred twenty-one thousand, three hundred twenty-one".