15223561 has 4 divisors (see below), whose sum is σ = 15510852. Its totient is φ = 14936272.

The previous prime is 15223547. The next prime is 15223567. The reversal of 15223561 is 16532251.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16532251 = 79 ⋅209269.

It can be written as a sum of positive squares in 2 ways, for example, as 12467961 + 2755600 = 3531^2 + 1660^2 .

It is a cyclic number.

It is not a de Polignac number, because 15223561 - 2⁷ = 15223433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15223567) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 143566 + ... + 143671.

It is an arithmetic number, because the mean of its divisors is an integer number (3877713).

Almost surely, 2^15223561 is an apocalyptic number.

It is an amenable number.

15223561 is a deficient number, since it is larger than the sum of its proper divisors (287291).

15223561 is an equidigital number, since it uses as much as digits as its factorization.

15223561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 287290.

The product of its digits is 1800, while the sum is 25.

The square root of 15223561 is about 3901.7382023913. The cubic root of 15223561 is about 247.8403900582.

The spelling of 15223561 in words is "fifteen million, two hundred twenty-three thousand, five hundred sixty-one".