51451355521 has 4 divisors (see below), whose sum is σ = 51550111044. Its totient is φ = 51352600000.

The previous prime is 51451355519. The next prime is 51451355531. The reversal of 51451355521 is 12555315415.

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 32774033296 + 18677322225 = 181036^2 + 136665^2 .

It is a cyclic number.

It is not a de Polignac number, because 51451355521 - 2¹ = 51451355519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51451355531) 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, 49376980 + ... + 49378021.

It is an arithmetic number, because the mean of its divisors is an integer number (12887527761).

Almost surely, 2^51451355521 is an apocalyptic number.

It is an amenable number.

51451355521 is a deficient number, since it is larger than the sum of its proper divisors (98755523).

51451355521 is an equidigital number, since it uses as much as digits as its factorization.

51451355521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98755522.

The product of its digits is 75000, while the sum is 37.

The spelling of 51451355521 in words is "fifty-one billion, four hundred fifty-one million, three hundred fifty-five thousand, five hundred twenty-one".