16561447 has 4 divisors (see below), whose sum is σ = 18927376. Its totient is φ = 14195520.

The previous prime is 16561423. The next prime is 16561469. The reversal of 16561447 is 74416561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74416561 = 739 ⋅100699.

It is a cyclic number.

It is not a de Polignac number, because 16561447 - 2¹¹ = 16559399 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 (16561147) 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, 1182954 + ... + 1182967.

It is an arithmetic number, because the mean of its divisors is an integer number (4731844).

Almost surely, 2^16561447 is an apocalyptic number.

16561447 is a deficient number, since it is larger than the sum of its proper divisors (2365929).

16561447 is an equidigital number, since it uses as much as digits as its factorization.

16561447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2365928.

The product of its digits is 20160, while the sum is 34.

The square root of 16561447 is about 4069.5757764170. The cubic root of 16561447 is about 254.8978034669.

The spelling of 16561447 in words is "sixteen million, five hundred sixty-one thousand, four hundred forty-seven".