19421000561 has 4 divisors (see below), whose sum is σ = 19490114724. Its totient is φ = 19351886400.

The previous prime is 19421000531. The next prime is 19421000563. The reversal of 19421000561 is 16500012491.

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

It can be written as a sum of positive squares in 2 ways, for example, as 9489682225 + 9931318336 = 97415^2 + 99656^2 .

It is a cyclic number.

It is not a de Polignac number, because 19421000561 - 2²² = 19416806257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19421000563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34556660 + ... + 34557221.

It is an arithmetic number, because the mean of its divisors is an integer number (4872528681).

Almost surely, 2^19421000561 is an apocalyptic number.

It is an amenable number.

19421000561 is a deficient number, since it is larger than the sum of its proper divisors (69114163).

19421000561 is an equidigital number, since it uses as much as digits as its factorization.

19421000561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69114162.

The product of its (nonzero) digits is 2160, while the sum is 29.

The spelling of 19421000561 in words is "nineteen billion, four hundred twenty-one million, five hundred sixty-one", and thus it is an aban number.