15660397 has 4 divisors (see below), whose sum is σ = 15671740. Its totient is φ = 15649056.

The previous prime is 15660367. The next prime is 15660419. The reversal of 15660397 is 79306651.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 14638276 + 1022121 = 3826^2 + 1011^2 .

It is a cyclic number.

It is not a de Polignac number, because 15660397 - 2⁷ = 15660269 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 (15660317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3258 + ... + 6475.

It is an arithmetic number, because the mean of its divisors is an integer number (3917935).

Almost surely, 2^15660397 is an apocalyptic number.

It is an amenable number.

15660397 is a deficient number, since it is larger than the sum of its proper divisors (11343).

15660397 is an equidigital number, since it uses as much as digits as its factorization.

15660397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11342.

The product of its (nonzero) digits is 34020, while the sum is 37.

The square root of 15660397 is about 3957.3219479845. The cubic root of 15660397 is about 250.1886416216.

The spelling of 15660397 in words is "fifteen million, six hundred sixty thousand, three hundred ninety-seven".