131221081 has 4 divisors (see below), whose sum is σ = 131245492. Its totient is φ = 131196672.

The previous prime is 131221063. The next prime is 131221093. The reversal of 131221081 is 180122131.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 21160000 + 110061081 = 4600^2 + 10491^2 .

It is a cyclic number.

It is not a de Polignac number, because 131221081 - 2⁷ = 131220953 is a prime.

It is a super-2 number, since 2×131221081² = 34437944197617122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (131221021) 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, 216 + ... + 16201.

It is an arithmetic number, because the mean of its divisors is an integer number (32811373).

Almost surely, 2^131221081 is an apocalyptic number.

It is an amenable number.

131221081 is a deficient number, since it is larger than the sum of its proper divisors (24411).

131221081 is an equidigital number, since it uses as much as digits as its factorization.

131221081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24410.

The product of its (nonzero) digits is 96, while the sum is 19.

The square root of 131221081 is about 11455.1770392255. The cubic root of 131221081 is about 508.1608510102.

The spelling of 131221081 in words is "one hundred thirty-one million, two hundred twenty-one thousand, eighty-one".