16561489 has 8 divisors (see below), whose sum is σ = 19123328. Its totient is φ = 14048640.

The previous prime is 16561469. The next prime is 16561507. The reversal of 16561489 is 98416561.

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

It is a cyclic number.

It is not a de Polignac number, because 16561489 - 2⁷ = 16561361 is a prime.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (16561469) 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, 11517 + ... + 12874.

It is an arithmetic number, because the mean of its divisors is an integer number (2390416).

Almost surely, 2^16561489 is an apocalyptic number.

It is an amenable number.

16561489 is a deficient number, since it is larger than the sum of its proper divisors (2561839).

16561489 is an equidigital number, since it uses as much as digits as its factorization.

16561489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24495.

The product of its digits is 51840, while the sum is 40.

The square root of 16561489 is about 4069.5809366567. The cubic root of 16561489 is about 254.8980189412.

The spelling of 16561489 in words is "sixteen million, five hundred sixty-one thousand, four hundred eighty-nine".