8720385 has 16 divisors (see below), whose sum is σ = 14162496. Its totient is φ = 4580928.

The previous prime is 8720347. The next prime is 8720389. The reversal of 8720385 is 5830278.

It is not a de Polignac number, because 8720385 - 2⁶ = 8720321 is a prime.

It is a super-2 number, since 2×8720385² = 152090229096450, which contains 22 as substring.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (8720389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3334 + ... + 5343.

It is an arithmetic number, because the mean of its divisors is an integer number (885156).

It is a Proth number, since it is equal to 2129 ⋅ 2¹² + 1 and 2129 < 2¹².

Almost surely, 2^8720385 is an apocalyptic number.

It is an amenable number.

8720385 is a deficient number, since it is larger than the sum of its proper divisors (5442111).

8720385 is a wasteful number, since it uses less digits than its factorization.

8720385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8752.

The product of its (nonzero) digits is 13440, while the sum is 33.

The square root of 8720385 is about 2953.0298000528. The cubic root of 8720385 is about 205.8315224735.

The spelling of 8720385 in words is "eight million, seven hundred twenty thousand, three hundred eighty-five".