51380776500721 has 2 divisors, whose sum is σ = 51380776500722. Its totient is φ = 51380776500720.

The previous prime is 51380776500643. The next prime is 51380776500769. The reversal of 51380776500721 is 12700567708315.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42329337210000 + 9051439290721 = 6506100^2 + 3008561^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51380776500721 is a prime.

It is a super-3 number, since 3×51380776500721³ (a number of 42 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (51380776800721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25690388250360 + 25690388250361.

It is an arithmetic number, because the mean of its divisors is an integer number (25690388250361).

Almost surely, 2^{51380776500721} is an apocalyptic number.

It is an amenable number.

51380776500721 is a deficient number, since it is larger than the sum of its proper divisors (1).

51380776500721 is an equidigital number, since it uses as much as digits as its factorization.

51380776500721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2469600, while the sum is 52.

The spelling of 51380776500721 in words is "fifty-one trillion, three hundred eighty billion, seven hundred seventy-six million, five hundred thousand, seven hundred twenty-one".