561442891 has 4 divisors (see below), whose sum is σ = 579553984. Its totient is φ = 543331800.

The previous prime is 561442831. The next prime is 561442909. The reversal of 561442891 is 198244165.

561442891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 561442891 - 2²³ = 553054283 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (561442801) 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, 9055500 + ... + 9055561.

It is an arithmetic number, because the mean of its divisors is an integer number (144888496).

Almost surely, 2^561442891 is an apocalyptic number.

561442891 is a deficient number, since it is larger than the sum of its proper divisors (18111093).

561442891 is a wasteful number, since it uses less digits than its factorization.

561442891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18111092.

The product of its digits is 69120, while the sum is 40.

The square root of 561442891 is about 23694.7861564522. The cubic root of 561442891 is about 824.9643772804.

The spelling of 561442891 in words is "five hundred sixty-one million, four hundred forty-two thousand, eight hundred ninety-one".