51599909 has 4 divisors (see below), whose sum is σ = 51674220. Its totient is φ = 51525600.

The previous prime is 51599893. The next prime is 51599917. The reversal of 51599909 is 90999515.

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 19166884 + 32433025 = 4378^2 + 5695^2 .

It is a cyclic number.

It is not a de Polignac number, because 51599909 - 2⁴ = 51599893 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 (51599929) 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, 36104 + ... + 37505.

It is an arithmetic number, because the mean of its divisors is an integer number (12918555).

Almost surely, 2^51599909 is an apocalyptic number.

It is an amenable number.

51599909 is a deficient number, since it is larger than the sum of its proper divisors (74311).

51599909 is an equidigital number, since it uses as much as digits as its factorization.

51599909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74310.

The product of its (nonzero) digits is 164025, while the sum is 47.

The square root of 51599909 is about 7183.3076643006. The cubic root of 51599909 is about 372.2913781591.

The spelling of 51599909 in words is "fifty-one million, five hundred ninety-nine thousand, nine hundred nine".