15561143 has 4 divisors (see below), whose sum is σ = 16758168. Its totient is φ = 14364120.

The previous prime is 15561131. The next prime is 15561157. The reversal of 15561143 is 34116551.

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

It is a cyclic number.

It is not a de Polignac number, because 15561143 - 2⁶ = 15561079 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 (15561173) 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, 598493 + ... + 598518.

It is an arithmetic number, because the mean of its divisors is an integer number (4189542).

Almost surely, 2^15561143 is an apocalyptic number.

15561143 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

15561143 is a deficient number, since it is larger than the sum of its proper divisors (1197025).

15561143 is a wasteful number, since it uses less digits than its factorization.

15561143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1197024.

The product of its digits is 1800, while the sum is 26.

The square root of 15561143 is about 3944.7614630038. The cubic root of 15561143 is about 249.6589643235.

Adding to 15561143 its reverse (34116551), we get a palindrome (49677694).

The spelling of 15561143 in words is "fifteen million, five hundred sixty-one thousand, one hundred forty-three".