13971561 has 4 divisors (see below), whose sum is σ = 18628752. Its totient is φ = 9314372.

The previous prime is 13971553. The next prime is 13971563. The reversal of 13971561 is 16517931.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 13971561 - 2³ = 13971553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (13971563) 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 3 ways as a sum of consecutive naturals, for example, 2328591 + ... + 2328596.

It is an arithmetic number, because the mean of its divisors is an integer number (4657188).

Almost surely, 2^13971561 is an apocalyptic number.

It is an amenable number.

13971561 is a deficient number, since it is larger than the sum of its proper divisors (4657191).

13971561 is an equidigital number, since it uses as much as digits as its factorization.

13971561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4657190.

The product of its digits is 5670, while the sum is 33.

The square root of 13971561 is about 3737.8551336294. The cubic root of 13971561 is about 240.8509204665.

The spelling of 13971561 in words is "thirteen million, nine hundred seventy-one thousand, five hundred sixty-one".