51105551505561 has 72 divisors (see below), whose sum is σ = 86850351983304. Its totient is φ = 28871052134400.

The previous prime is 51105551505553. The next prime is 51105551505563. The reversal of 51105551505561 is 16550515550115.

It can be written as a sum of positive squares in 4 ways, for example, as 21196410849936 + 29909140655625 = 4603956^2 + 5468925^2 .

It is not a de Polignac number, because 51105551505561 - 2³ = 51105551505553 is a prime.

It is a super-2 number, since 2×51105551505561² (a number of 28 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (51105551505563) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 29123655 + ... + 30828531.

It is an arithmetic number, because the mean of its divisors is an integer number (1206254888657).

Almost surely, 2^{51105551505561} is an apocalyptic number.

It is an amenable number.

51105551505561 is a deficient number, since it is larger than the sum of its proper divisors (35744800477743).

51105551505561 is a wasteful number, since it uses less digits than its factorization.

51105551505561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1705671 (or 1705661 counting only the distinct ones).

The product of its (nonzero) digits is 468750, while the sum is 45.

The spelling of 51105551505561 in words is "fifty-one trillion, one hundred five billion, five hundred fifty-one million, five hundred five thousand, five hundred sixty-one".