15666641 has 8 divisors (see below), whose sum is σ = 16514280. Its totient is φ = 14839552.

The previous prime is 15666631. The next prime is 15666661. The reversal of 15666641 is 14666651.

It can be written as a sum of positive squares in 4 ways, for example, as 5452225 + 10214416 = 2335^2 + 3196^2 .

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 15666641 - 2²² = 11472337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15666631) 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, 3560 + ... + 6633.

It is an arithmetic number, because the mean of its divisors is an integer number (2064285).

Almost surely, 2^15666641 is an apocalyptic number.

It is an amenable number.

15666641 is a deficient number, since it is larger than the sum of its proper divisors (847639).

15666641 is a wasteful number, since it uses less digits than its factorization.

15666641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10275.

The product of its digits is 25920, while the sum is 35.

The square root of 15666641 is about 3958.1107867264. The cubic root of 15666641 is about 250.2218883373.

The spelling of 15666641 in words is "fifteen million, six hundred sixty-six thousand, six hundred forty-one".