47909809 has 4 divisors (see below), whose sum is σ = 48153204. Its totient is φ = 47666416.

The previous prime is 47909803. The next prime is 47909831. The reversal of 47909809 is 90890974.

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 46621584 + 1288225 = 6828^2 + 1135^2 .

It is a cyclic number.

It is not a de Polignac number, because 47909809 - 2¹⁷ = 47778737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (47909803) 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, 121402 + ... + 121795.

It is an arithmetic number, because the mean of its divisors is an integer number (12038301).

Almost surely, 2^47909809 is an apocalyptic number.

It is an amenable number.

47909809 is a deficient number, since it is larger than the sum of its proper divisors (243395).

47909809 is a wasteful number, since it uses less digits than its factorization.

47909809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243394.

The product of its (nonzero) digits is 163296, while the sum is 46.

The square root of 47909809 is about 6921.6911950765. The cubic root of 47909809 is about 363.1963537359.

The spelling of 47909809 in words is "forty-seven million, nine hundred nine thousand, eight hundred nine".