131001221 has 16 divisors (see below), whose sum is σ = 144209520. Its totient is φ = 118264320.

The previous prime is 131001217. The next prime is 131001229. The reversal of 131001221 is 122100131.

It can be written as a sum of positive squares in 8 ways, for example, as 75498721 + 55502500 = 8689^2 + 7450^2 .

It is a cyclic number.

It is not a de Polignac number, because 131001221 - 2² = 131001217 is a prime.

It is a super-2 number, since 2×131001221² = 34322639806981682, which contains 22 as substring.

131001221 is a modest number, since divided by 1221 gives 131 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131001229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 184415 + ... + 185123.

It is an arithmetic number, because the mean of its divisors is an integer number (9013095).

Almost surely, 2^131001221 is an apocalyptic number.

It is an amenable number.

131001221 is a deficient number, since it is larger than the sum of its proper divisors (13208299).

131001221 is a wasteful number, since it uses less digits than its factorization.

131001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1016.

The product of its (nonzero) digits is 12, while the sum is 11.

The square root of 131001221 is about 11445.5764817680. The cubic root of 131001221 is about 507.8768857110.

Adding to 131001221 its reverse (122100131), we get a palindrome (253101352).

The spelling of 131001221 in words is "one hundred thirty-one million, one thousand, two hundred twenty-one".