81701751 has 4 divisors (see below), whose sum is σ = 108935672. Its totient is φ = 54467832.

The previous prime is 81701749. The next prime is 81701783. The reversal of 81701751 is 15710718.

It is a happy number.

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

It is not a de Polignac number, because 81701751 - 2¹ = 81701749 is a prime.

It is a super-2 number, since 2×81701751² = 13350352232932002, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81701791) 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, 13616956 + ... + 13616961.

It is an arithmetic number, because the mean of its divisors is an integer number (27233918).

Almost surely, 2^81701751 is an apocalyptic number.

81701751 is a deficient number, since it is larger than the sum of its proper divisors (27233921).

81701751 is a wasteful number, since it uses less digits than its factorization.

81701751 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27233920.

The product of its (nonzero) digits is 1960, while the sum is 30.

The square root of 81701751 is about 9038.9020904090. The cubic root of 81701751 is about 433.9207862252.

The spelling of 81701751 in words is "eighty-one million, seven hundred one thousand, seven hundred fifty-one".