47309821 has 4 divisors (see below), whose sum is σ = 50949052. Its totient is φ = 43670592.

The previous prime is 47309809. The next prime is 47309833. The reversal of 47309821 is 12890374.

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

It is an interprime number because it is at equal distance from previous prime (47309809) and next prime (47309833).

It can be written as a sum of positive squares in 2 ways, for example, as 21958596 + 25351225 = 4686^2 + 5035^2 .

It is a cyclic number.

It is not a de Polignac number, because 47309821 - 2¹⁷ = 47178749 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 (47309851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1819596 + ... + 1819621.

It is an arithmetic number, because the mean of its divisors is an integer number (12737263).

Almost surely, 2^47309821 is an apocalyptic number.

It is an amenable number.

47309821 is a deficient number, since it is larger than the sum of its proper divisors (3639231).

47309821 is a wasteful number, since it uses less digits than its factorization.

47309821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3639230.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 47309821 is about 6878.2135035196. The cubic root of 47309821 is about 361.6738436663.

The spelling of 47309821 in words is "forty-seven million, three hundred nine thousand, eight hundred twenty-one".