51645504557 has 4 divisors (see below), whose sum is σ = 51750689376. Its totient is φ = 51540319740.

The previous prime is 51645504553. The next prime is 51645504571. The reversal of 51645504557 is 75540554615.

51645504557 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, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 75540554615 = 5 ⋅15108110923.

It is a cyclic number.

It is not a de Polignac number, because 51645504557 - 2² = 51645504553 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51645504553) 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, 52591673 + ... + 52592654.

It is an arithmetic number, because the mean of its divisors is an integer number (12937672344).

Almost surely, 2^51645504557 is an apocalyptic number.

It is an amenable number.

51645504557 is a deficient number, since it is larger than the sum of its proper divisors (105184819).

51645504557 is a wasteful number, since it uses less digits than its factorization.

51645504557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105184818.

The product of its (nonzero) digits is 2100000, while the sum is 47.

The spelling of 51645504557 in words is "fifty-one billion, six hundred forty-five million, five hundred four thousand, five hundred fifty-seven".