81871550 has 24 divisors (see below), whose sum is σ = 152656896. Its totient is φ = 32667840.

The previous prime is 81871519. The next prime is 81871597. The reversal of 81871550 is 5517818.

It is a self number, because there is not a number n which added to its sum of digits gives 81871550.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 21059 + ... + 24641.

It is an arithmetic number, because the mean of its divisors is an integer number (6360704).

Almost surely, 2^81871550 is an apocalyptic number.

81871550 is a deficient number, since it is larger than the sum of its proper divisors (70785346).

81871550 is a wasteful number, since it uses less digits than its factorization.

81871550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4052 (or 4047 counting only the distinct ones).

The product of its (nonzero) digits is 11200, while the sum is 35.

The square root of 81871550 is about 9048.2898936760. The cubic root of 81871550 is about 434.2211809800.

The spelling of 81871550 in words is "eighty-one million, eight hundred seventy-one thousand, five hundred fifty".