85728731 has 4 divisors (see below), whose sum is σ = 93522264. Its totient is φ = 77935200.

The previous prime is 85728707. The next prime is 85728743. The reversal of 85728731 is 13782758.

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-85728731 is a prime.

It is a super-2 number, since 2×85728731² = 14698830637740722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (85728781) 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, 3896750 + ... + 3896771.

It is an arithmetic number, because the mean of its divisors is an integer number (23380566).

Almost surely, 2^85728731 is an apocalyptic number.

85728731 is a deficient number, since it is larger than the sum of its proper divisors (7793533).

85728731 is a wasteful number, since it uses less digits than its factorization.

85728731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7793532.

The product of its digits is 94080, while the sum is 41.

The square root of 85728731 is about 9258.9810994515. The cubic root of 85728731 is about 440.9359055902.

The spelling of 85728731 in words is "eighty-five million, seven hundred twenty-eight thousand, seven hundred thirty-one".