51332209 has 4 divisors (see below), whose sum is σ = 52719604. Its totient is φ = 49944816.

The previous prime is 51332189. The next prime is 51332221. The reversal of 51332209 is 90223315.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 34751025 + 16581184 = 5895^2 + 4072^2 .

It is a cyclic number.

It is not a de Polignac number, because 51332209 - 2⁷ = 51332081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51332269) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 693642 + ... + 693715.

It is an arithmetic number, because the mean of its divisors is an integer number (13179901).

Almost surely, 2^51332209 is an apocalyptic number.

It is an amenable number.

51332209 is a deficient number, since it is larger than the sum of its proper divisors (1387395).

51332209 is a wasteful number, since it uses less digits than its factorization.

51332209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1387394.

The product of its (nonzero) digits is 1620, while the sum is 25.

The square root of 51332209 is about 7164.6499565575. The cubic root of 51332209 is about 371.6464464680.

The spelling of 51332209 in words is "fifty-one million, three hundred thirty-two thousand, two hundred nine".