13131621 has 6 divisors (see below), whose sum is σ = 18967910. Its totient is φ = 8754408.

The previous prime is 13131607. The next prime is 13131623. The reversal of 13131621 is 12613131.

13131621 is a `hidden beast` number, since 13 + 1 + 31 + 621 = 666.

It can be written as a sum of positive squares in only one way, i.e., 11655396 + 1476225 = 3414^2 + 1215^2 .

It is not a de Polignac number, because 13131621 - 2⁵ = 13131589 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 13131594 and 13131603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13131623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 729526 + ... + 729543.

Almost surely, 2^13131621 is an apocalyptic number.

It is an amenable number.

13131621 is a deficient number, since it is larger than the sum of its proper divisors (5836289).

13131621 is a wasteful number, since it uses less digits than its factorization.

13131621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1459075 (or 1459072 counting only the distinct ones).

The product of its digits is 108, while the sum is 18.

The square root of 13131621 is about 3623.7578561488. The cubic root of 13131621 is about 235.9243569218.

Adding to 13131621 its reverse (12613131), we get a palindrome (25744752).

The spelling of 13131621 in words is "thirteen million, one hundred thirty-one thousand, six hundred twenty-one".