13661999 has 8 divisors (see below), whose sum is σ = 15578640. Its totient is φ = 11869056.

The previous prime is 13661971. The next prime is 13662013. The reversal of 13661999 is 99916631.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13661999 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 (13661909) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30689 + ... + 31130.

It is an arithmetic number, because the mean of its divisors is an integer number (1947330).

Almost surely, 2^13661999 is an apocalyptic number.

13661999 is a deficient number, since it is larger than the sum of its proper divisors (1916641).

13661999 is a wasteful number, since it uses less digits than its factorization.

13661999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61849.

The product of its digits is 78732, while the sum is 44.

The square root of 13661999 is about 3696.2141442292. The cubic root of 13661999 is about 239.0588080282.

The spelling of 13661999 in words is "thirteen million, six hundred sixty-one thousand, nine hundred ninety-nine".