16561135 has 4 divisors (see below), whose sum is σ = 19873368. Its totient is φ = 13248904.

The previous prime is 16561093. The next prime is 16561147. The reversal of 16561135 is 53116561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 53116561 = 2557 ⋅20773.

It is a cyclic number.

It is not a de Polignac number, because 16561135 - 2²¹ = 14463983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1656109 + ... + 1656118.

It is an arithmetic number, because the mean of its divisors is an integer number (4968342).

Almost surely, 2^16561135 is an apocalyptic number.

16561135 is a deficient number, since it is larger than the sum of its proper divisors (3312233).

16561135 is an equidigital number, since it uses as much as digits as its factorization.

16561135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3312232.

The product of its digits is 2700, while the sum is 28.

The square root of 16561135 is about 4069.5374430026. The cubic root of 16561135 is about 254.8962027893.

Adding to 16561135 its reverse (53116561), we get a palindrome (69677696).

The spelling of 16561135 in words is "sixteen million, five hundred sixty-one thousand, one hundred thirty-five".