51431440217 has 2 divisors, whose sum is σ = 51431440218. Its totient is φ = 51431440216.

The previous prime is 51431440171. The next prime is 51431440223. The reversal of 51431440217 is 71204413415.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50731255696 + 700184521 = 225236^2 + 26461^2 .

It is a cyclic number.

It is not a de Polignac number, because 51431440217 - 2⁶ = 51431440153 is a prime.

It is not a weakly prime, because it can be changed into another prime (51431440237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25715720108 + 25715720109.

It is an arithmetic number, because the mean of its divisors is an integer number (25715720109).

Almost surely, 2^51431440217 is an apocalyptic number.

It is an amenable number.

51431440217 is a deficient number, since it is larger than the sum of its proper divisors (1).

51431440217 is an equidigital number, since it uses as much as digits as its factorization.

51431440217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13440, while the sum is 32.

The spelling of 51431440217 in words is "fifty-one billion, four hundred thirty-one million, four hundred forty thousand, two hundred seventeen".