51513041221 has 2 divisors, whose sum is σ = 51513041222. Its totient is φ = 51513041220.

The previous prime is 51513041077. The next prime is 51513041231. The reversal of 51513041221 is 12214031515.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 33328518721 + 18184522500 = 182561^2 + 134850^2 .

It is a cyclic number.

It is not a de Polignac number, because 51513041221 - 2³¹ = 49365557573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51513041231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25756520610 + 25756520611.

It is an arithmetic number, because the mean of its divisors is an integer number (25756520611).

Almost surely, 2^51513041221 is an apocalyptic number.

It is an amenable number.

51513041221 is a deficient number, since it is larger than the sum of its proper divisors (1).

51513041221 is an equidigital number, since it uses as much as digits as its factorization.

51513041221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1200, while the sum is 25.

Adding to 51513041221 its reverse (12214031515), we get a palindrome (63727072736).

The spelling of 51513041221 in words is "fifty-one billion, five hundred thirteen million, forty-one thousand, two hundred twenty-one".