13999661 has 8 divisors (see below), whose sum is σ = 15119160. Its totient is φ = 12886272.

The previous prime is 13999651. The next prime is 13999673. The reversal of 13999661 is 16699931.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 902500 + 13097161 = 950^2 + 3619^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 13999661 - 2⁶ = 13999597 is a prime.

It is a super-2 number, since 2×13999661² = 391981016229842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13999621) 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, 4001 + ... + 6633.

It is an arithmetic number, because the mean of its divisors is an integer number (1889895).

Almost surely, 2^13999661 is an apocalyptic number.

It is an amenable number.

13999661 is a deficient number, since it is larger than the sum of its proper divisors (1119499).

13999661 is a wasteful number, since it uses less digits than its factorization.

13999661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3055.

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

The square root of 13999661 is about 3741.6120857192. The cubic root of 13999661 is about 241.0122810727.

The spelling of 13999661 in words is "thirteen million, nine hundred ninety-nine thousand, six hundred sixty-one".