13782521 has 4 divisors (see below), whose sum is σ = 13800612. Its totient is φ = 13764432.

The previous prime is 13782499. The next prime is 13782551. The reversal of 13782521 is 12528731.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12528731 = 71 ⋅176461.

It can be written as a sum of positive squares in 2 ways, for example, as 3024121 + 10758400 = 1739^2 + 3280^2 .

It is a cyclic number.

It is not a de Polignac number, because 13782521 - 2¹⁰ = 13781497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13782551) 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, 7850 + ... + 9443.

It is an arithmetic number, because the mean of its divisors is an integer number (3450153).

Almost surely, 2^13782521 is an apocalyptic number.

It is an amenable number.

13782521 is a deficient number, since it is larger than the sum of its proper divisors (18091).

13782521 is an equidigital number, since it uses as much as digits as its factorization.

13782521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18090.

The product of its digits is 3360, while the sum is 29.

The square root of 13782521 is about 3712.4817844671. The cubic root of 13782521 is about 239.7597190087.

The spelling of 13782521 in words is "thirteen million, seven hundred eighty-two thousand, five hundred twenty-one".