15561897 has 8 divisors (see below), whose sum is σ = 22345344. Its totient is φ = 9576528.

The previous prime is 15561881. The next prime is 15561911. The reversal of 15561897 is 79816551.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 15561897 - 2⁴ = 15561881 is a prime.

It is not an unprimeable number, because it can be changed into a prime (15561827) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 199473 + ... + 199550.

It is an arithmetic number, because the mean of its divisors is an integer number (2793168).

Almost surely, 2^15561897 is an apocalyptic number.

It is an amenable number.

15561897 is a deficient number, since it is larger than the sum of its proper divisors (6783447).

15561897 is a wasteful number, since it uses less digits than its factorization.

15561897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399039.

The product of its digits is 75600, while the sum is 42.

The square root of 15561897 is about 3944.8570316299. The cubic root of 15561897 is about 249.6629965856.

The spelling of 15561897 in words is "fifteen million, five hundred sixty-one thousand, eight hundred ninety-seven".