561813821539 has 4 divisors (see below), whose sum is σ = 586240509456. Its totient is φ = 537387133624.

The previous prime is 561813821537. The next prime is 561813821549. The reversal of 561813821539 is 935128318165.

It is a happy number.

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 561813821539 - 2¹ = 561813821537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (561813821537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12213343924 + ... + 12213343969.

It is an arithmetic number, because the mean of its divisors is an integer number (146560127364).

Almost surely, 2^561813821539 is an apocalyptic number.

561813821539 is a deficient number, since it is larger than the sum of its proper divisors (24426687917).

561813821539 is a wasteful number, since it uses less digits than its factorization.

561813821539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24426687916.

The product of its digits is 1555200, while the sum is 52.

The spelling of 561813821539 in words is "five hundred sixty-one billion, eight hundred thirteen million, eight hundred twenty-one thousand, five hundred thirty-nine".