81987127 has 4 divisors (see below), whose sum is σ = 82509496. Its totient is φ = 81464760.

The previous prime is 81987121. The next prime is 81987133. The reversal of 81987127 is 72178918.

It is a happy number.

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

It is an interprime number because it is at equal distance from previous prime (81987121) and next prime (81987133).

It is a cyclic number.

It is not a de Polignac number, because 81987127 - 2³ = 81987119 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 (81987121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 260949 + ... + 261262.

It is an arithmetic number, because the mean of its divisors is an integer number (20627374).

Almost surely, 2^81987127 is an apocalyptic number.

81987127 is a deficient number, since it is larger than the sum of its proper divisors (522369).

81987127 is a wasteful number, since it uses less digits than its factorization.

81987127 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 522368.

The product of its digits is 56448, while the sum is 43.

The square root of 81987127 is about 9054.6743177212. The cubic root of 81987127 is about 434.4254130334.

The spelling of 81987127 in words is "eighty-one million, nine hundred eighty-seven thousand, one hundred twenty-seven".