81268751 has 4 divisors (see below), whose sum is σ = 82057872. Its totient is φ = 80479632.

The previous prime is 81268739. The next prime is 81268777. The reversal of 81268751 is 15786218.

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-81268751 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 (81268711) 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, 394406 + ... + 394611.

It is an arithmetic number, because the mean of its divisors is an integer number (20514468).

Almost surely, 2^81268751 is an apocalyptic number.

81268751 is a deficient number, since it is larger than the sum of its proper divisors (789121).

81268751 is a wasteful number, since it uses less digits than its factorization.

81268751 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 789120.

The product of its digits is 26880, while the sum is 38.

The square root of 81268751 is about 9014.9182469948. The cubic root of 81268751 is about 433.1528687732.

The spelling of 81268751 in words is "eighty-one million, two hundred sixty-eight thousand, seven hundred fifty-one".