51564720841 has 4 divisors (see below), whose sum is σ = 54597939732. Its totient is φ = 48531501952.

The previous prime is 51564720839. The next prime is 51564720869. The reversal of 51564720841 is 14802746515.

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 18774754441 + 32789966400 = 137021^2 + 181080^2 .

It is a cyclic number.

It is not a de Polignac number, because 51564720841 - 2¹ = 51564720839 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51564120841) 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, 1516609420 + ... + 1516609453.

It is an arithmetic number, because the mean of its divisors is an integer number (13649484933).

Almost surely, 2^51564720841 is an apocalyptic number.

It is an amenable number.

51564720841 is a deficient number, since it is larger than the sum of its proper divisors (3033218891).

51564720841 is a wasteful number, since it uses less digits than its factorization.

51564720841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3033218890.

The product of its (nonzero) digits is 268800, while the sum is 43.

The spelling of 51564720841 in words is "fifty-one billion, five hundred sixty-four million, seven hundred twenty thousand, eight hundred forty-one".