15995666 has 4 divisors (see below), whose sum is σ = 23993502. Its totient is φ = 7997832.

The previous prime is 15995653. The next prime is 15995669. The reversal of 15995666 is 66659951.

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

It can be written as a sum of positive squares in only one way, i.e., 14250625 + 1745041 = 3775^2 + 1321^2 .

It is a super-2 number, since 2×15995666² = 511722661567112, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 15995666.

It is not an unprimeable number, because it can be changed into a prime (15995669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3998915 + ... + 3998918.

Almost surely, 2^15995666 is an apocalyptic number.

15995666 is a deficient number, since it is larger than the sum of its proper divisors (7997836).

15995666 is an equidigital number, since it uses as much as digits as its factorization.

15995666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7997835.

The product of its digits is 437400, while the sum is 47.

The square root of 15995666 is about 3999.4582133084. The cubic root of 15995666 is about 251.9614558501.

It can be divided in two parts, 15995 and 666, that added together give a palindrome (16661).

The spelling of 15995666 in words is "fifteen million, nine hundred ninety-five thousand, six hundred sixty-six".