4721809 has 4 divisors (see below), whose sum is σ = 4884660. Its totient is φ = 4558960.

The previous prime is 4721791. The next prime is 4721813. The reversal of 4721809 is 9081274.

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 2334784 + 2387025 = 1528^2 + 1545^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4721809 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (4721819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81382 + ... + 81439.

It is an arithmetic number, because the mean of its divisors is an integer number (1221165).

Almost surely, 2^4721809 is an apocalyptic number.

It is an amenable number.

4721809 is a deficient number, since it is larger than the sum of its proper divisors (162851).

4721809 is a wasteful number, since it uses less digits than its factorization.

4721809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162850.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 4721809 is about 2172.9723882277. The cubic root of 4721809 is about 167.7655578168.

The spelling of 4721809 in words is "four million, seven hundred twenty-one thousand, eight hundred nine".