15561839 has 2 divisors, whose sum is σ = 15561840. Its totient is φ = 15561838.

The previous prime is 15561827. The next prime is 15561853. The reversal of 15561839 is 93816551.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 15561839 - 2²⁰ = 14513263 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15561809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7780919 + 7780920.

It is an arithmetic number, because the mean of its divisors is an integer number (7780920).

Almost surely, 2^15561839 is an apocalyptic number.

15561839 is a deficient number, since it is larger than the sum of its proper divisors (1).

15561839 is an equidigital number, since it uses as much as digits as its factorization.

15561839 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32400, while the sum is 38.

The square root of 15561839 is about 3944.8496802793. The cubic root of 15561839 is about 249.6626864162.

The spelling of 15561839 in words is "fifteen million, five hundred sixty-one thousand, eight hundred thirty-nine".