81716751 has 24 divisors (see below), whose sum is σ = 123954480. Its totient is φ = 51803136.

The previous prime is 81716749. The next prime is 81716827. The reversal of 81716751 is 15761718.

It is a happy number.

It is not a de Polignac number, because 81716751 - 2¹ = 81716749 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81716351) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15151 + ... + 19823.

It is an arithmetic number, because the mean of its divisors is an integer number (5164770).

Almost surely, 2^81716751 is an apocalyptic number.

81716751 is a deficient number, since it is larger than the sum of its proper divisors (42237729).

81716751 is a wasteful number, since it uses less digits than its factorization.

81716751 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4775 (or 4772 counting only the distinct ones).

The product of its digits is 11760, while the sum is 36.

The square root of 81716751 is about 9039.7317991188. The cubic root of 81716751 is about 433.9473397707.

The spelling of 81716751 in words is "eighty-one million, seven hundred sixteen thousand, seven hundred fifty-one".