81632751 has 4 divisors (see below), whose sum is σ = 108843672. Its totient is φ = 54421832.

The previous prime is 81632743. The next prime is 81632777. The reversal of 81632751 is 15723618.

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

It is a cyclic number.

It is not a de Polignac number, because 81632751 - 2³ = 81632743 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81632051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13605456 + ... + 13605461.

It is an arithmetic number, because the mean of its divisors is an integer number (27210918).

Almost surely, 2^81632751 is an apocalyptic number.

81632751 is a deficient number, since it is larger than the sum of its proper divisors (27210921).

81632751 is a wasteful number, since it uses less digits than its factorization.

81632751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27210920.

The product of its digits is 10080, while the sum is 33.

The square root of 81632751 is about 9035.0844489689. The cubic root of 81632751 is about 433.7985980368.

The spelling of 81632751 in words is "eighty-one million, six hundred thirty-two thousand, seven hundred fifty-one".