51505311521 has 8 divisors (see below), whose sum is σ = 52496803464. Its totient is φ = 50523217920.

The previous prime is 51505311503. The next prime is 51505311617. The reversal of 51505311521 is 12511350515.

It can be written as a sum of positive squares in 4 ways, for example, as 5400633121 + 46104678400 = 73489^2 + 214720^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51505311521 - 2¹⁸ = 51505049377 is a prime.

It is a super-2 number, since 2×51505311521² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51505311421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2338520 + ... + 2360441.

It is an arithmetic number, because the mean of its divisors is an integer number (6562100433).

Almost surely, 2^51505311521 is an apocalyptic number.

It is an amenable number.

51505311521 is a deficient number, since it is larger than the sum of its proper divisors (991491943).

51505311521 is a wasteful number, since it uses less digits than its factorization.

51505311521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4699171.

The product of its (nonzero) digits is 3750, while the sum is 29.

The spelling of 51505311521 in words is "fifty-one billion, five hundred five million, three hundred eleven thousand, five hundred twenty-one".