17720047 has 4 divisors (see below), whose sum is σ = 17735760. Its totient is φ = 17704336.

The previous prime is 17720041. The next prime is 17720063. The reversal of 17720047 is 74002771.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-17720047 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 17719997 and 17720024.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (17720041) 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, 6022 + ... + 8467.

It is an arithmetic number, because the mean of its divisors is an integer number (4433940).

Almost surely, 2^17720047 is an apocalyptic number.

17720047 is a deficient number, since it is larger than the sum of its proper divisors (15713).

17720047 is a wasteful number, since it uses less digits than its factorization.

17720047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15712.

The product of its (nonzero) digits is 2744, while the sum is 28.

The square root of 17720047 is about 4209.5186185596. The cubic root of 17720047 is about 260.7083592787.

The spelling of 17720047 in words is "seventeen million, seven hundred twenty thousand, forty-seven".