51713209 has 2 divisors, whose sum is σ = 51713210. Its totient is φ = 51713208.

The previous prime is 51713173. The next prime is 51713237. The reversal of 51713209 is 90231715.

It is an a-pointer prime, because the next prime (51713237) can be obtained adding 51713209 to its sum of digits (28).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51437584 + 275625 = 7172^2 + 525^2 .

It is a cyclic number.

It is not a de Polignac number, because 51713209 - 2¹⁷ = 51582137 is a prime.

It is not a weakly prime, because it can be changed into another prime (51713509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25856604 + 25856605.

It is an arithmetic number, because the mean of its divisors is an integer number (25856605).

Almost surely, 2^51713209 is an apocalyptic number.

It is an amenable number.

51713209 is a deficient number, since it is larger than the sum of its proper divisors (1).

51713209 is an equidigital number, since it uses as much as digits as its factorization.

51713209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 51713209 is about 7191.1896790448. The cubic root of 51713209 is about 372.5636640281.

The spelling of 51713209 in words is "fifty-one million, seven hundred thirteen thousand, two hundred nine".