15566401 has 4 divisors (see below), whose sum is σ = 15754032. Its totient is φ = 15378772.

The previous prime is 15566363. The next prime is 15566413. The reversal of 15566401 is 10466551.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 15566401 - 2⁷ = 15566273 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 15566401.

It is not an unprimeable number, because it can be changed into a prime (15566461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 93691 + ... + 93856.

It is an arithmetic number, because the mean of its divisors is an integer number (3938508).

Almost surely, 2^15566401 is an apocalyptic number.

It is an amenable number.

15566401 is a deficient number, since it is larger than the sum of its proper divisors (187631).

15566401 is an equidigital number, since it uses as much as digits as its factorization.

15566401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187630.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 15566401 is about 3945.4278601946. The cubic root of 15566401 is about 249.6870804889.

The spelling of 15566401 in words is "fifteen million, five hundred sixty-six thousand, four hundred one".