13731021 has 6 divisors (see below), whose sum is σ = 19833710. Its totient is φ = 9154008.

The previous prime is 13731017. The next prime is 13731031. The reversal of 13731021 is 12013731.

It can be written as a sum of positive squares in only one way, i.e., 13616100 + 114921 = 3690^2 + 339^2 .

It is not a de Polignac number, because 13731021 - 2² = 13731017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 13730985 and 13731003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13731001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 762826 + ... + 762843.

Almost surely, 2^13731021 is an apocalyptic number.

It is an amenable number.

13731021 is a deficient number, since it is larger than the sum of its proper divisors (6102689).

13731021 is a wasteful number, since it uses less digits than its factorization.

13731021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1525675 (or 1525672 counting only the distinct ones).

The product of its (nonzero) digits is 126, while the sum is 18.

The square root of 13731021 is about 3705.5392320147. The cubic root of 13731021 is about 239.4607162118.

Adding to 13731021 its reverse (12013731), we get a palindrome (25744752).

The spelling of 13731021 in words is "thirteen million, seven hundred thirty-one thousand, twenty-one".