51716209 has 6 divisors (see below), whose sum is σ = 52311830. Its totient is φ = 51127296.

The previous prime is 51716207. The next prime is 51716219. The reversal of 51716209 is 90261715.

It can be written as a sum of positive squares in 3 ways, for example, as 1703025 + 50013184 = 1305^2 + 7072^2 .

It is not a de Polignac number, because 51716209 - 2¹ = 51716207 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51716207) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4657 + ... + 11185.

Almost surely, 2^51716209 is an apocalyptic number.

It is an amenable number.

51716209 is a deficient number, since it is larger than the sum of its proper divisors (595621).

51716209 is an frugal number, since it uses more digits than its factorization.

51716209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6707 (or 6618 counting only the distinct ones).

The product of its (nonzero) digits is 3780, while the sum is 31.

The square root of 51716209 is about 7191.3982645936. The cubic root of 51716209 is about 372.5708683085.

The spelling of 51716209 in words is "fifty-one million, seven hundred sixteen thousand, two hundred nine".