13661287 has 4 divisors (see below), whose sum is σ = 14255280. Its totient is φ = 13067296.

The previous prime is 13661281. The next prime is 13661303. The reversal of 13661287 is 78216631.

13661287 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 13661287 - 2³ = 13661279 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13661281) 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, 296962 + ... + 297007.

It is an arithmetic number, because the mean of its divisors is an integer number (3563820).

Almost surely, 2^13661287 is an apocalyptic number.

13661287 is a deficient number, since it is larger than the sum of its proper divisors (593993).

13661287 is an equidigital number, since it uses as much as digits as its factorization.

13661287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 593992.

The product of its digits is 12096, while the sum is 34.

The square root of 13661287 is about 3696.1178282084. The cubic root of 13661287 is about 239.0546550774.

It can be divided in two parts, 13 and 661287, that multiplied together give a triangular number (8596731 = T₄₁₄₆).

The spelling of 13661287 in words is "thirteen million, six hundred sixty-one thousand, two hundred eighty-seven".