51050221561 has 4 divisors (see below), whose sum is σ = 51067725412. Its totient is φ = 51032717712.

The previous prime is 51050221549. The next prime is 51050221567. The reversal of 51050221561 is 16512205015.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16512205015 = 5 ⋅3302441003.

It can be written as a sum of positive squares in 2 ways, for example, as 25624005625 + 25426215936 = 160075^2 + 159456^2 .

It is a cyclic number.

It is not a de Polignac number, because 51050221561 - 2⁷ = 51050221433 is a prime.

It is a super-2 number, since 2×51050221561² (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 (51050221567) 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, 8747550 + ... + 8753383.

It is an arithmetic number, because the mean of its divisors is an integer number (12766931353).

Almost surely, 2^51050221561 is an apocalyptic number.

It is an amenable number.

51050221561 is a deficient number, since it is larger than the sum of its proper divisors (17503851).

51050221561 is a wasteful number, since it uses less digits than its factorization.

51050221561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17503850.

The product of its (nonzero) digits is 3000, while the sum is 28.

Adding to 51050221561 its reverse (16512205015), we get a palindrome (67562426576).

The spelling of 51050221561 in words is "fifty-one billion, fifty million, two hundred twenty-one thousand, five hundred sixty-one".