81887638 has 8 divisors (see below), whose sum is σ = 140378832. Its totient is φ = 35094696.

The previous prime is 81887633. The next prime is 81887671. The reversal of 81887638 is 83678818.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 81887591 and 81887600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81887633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2924545 + ... + 2924572.

It is an arithmetic number, because the mean of its divisors is an integer number (17547354).

Almost surely, 2^81887638 is an apocalyptic number.

81887638 is a deficient number, since it is larger than the sum of its proper divisors (58491194).

81887638 is a wasteful number, since it uses less digits than its factorization.

81887638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5849126.

The product of its digits is 516096, while the sum is 49.

The square root of 81887638 is about 9049.1788577749. The cubic root of 81887638 is about 434.2496210296.

The spelling of 81887638 in words is "eighty-one million, eight hundred eighty-seven thousand, six hundred thirty-eight".