16561442 has 4 divisors (see below), whose sum is σ = 24842166. Its totient is φ = 8280720.

The previous prime is 16561423. The next prime is 16561469. The reversal of 16561442 is 24416561.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 16248961 + 312481 = 4031^2 + 559^2 .

It is a super-2 number, since 2×16561442² = 548562722238728, which contains 22 as substring.

It is a nialpdrome in base 16.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4140359 + ... + 4140362.

Almost surely, 2^16561442 is an apocalyptic number.

16561442 is a deficient number, since it is larger than the sum of its proper divisors (8280724).

16561442 is an equidigital number, since it uses as much as digits as its factorization.

16561442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8280723.

The product of its digits is 5760, while the sum is 29.

The square root of 16561442 is about 4069.5751621023. The cubic root of 16561442 is about 254.8977778152.

The spelling of 16561442 in words is "sixteen million, five hundred sixty-one thousand, four hundred forty-two".