81849872 has 80 divisors (see below), whose sum is σ = 182280000. Its totient is φ = 35292672.

The previous prime is 81849857. The next prime is 81849881. The reversal of 81849872 is 27894818.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 549254 + ... + 549402.

It is an arithmetic number, because the mean of its divisors is an integer number (2278500).

Almost surely, 2^81849872 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81849872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91140000).

81849872 is an abundant number, since it is smaller than the sum of its proper divisors (100430128).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81849872 is a wasteful number, since it uses less digits than its factorization.

81849872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328 (or 322 counting only the distinct ones).

The product of its digits is 258048, while the sum is 47.

The square root of 81849872 is about 9047.0919084532. The cubic root of 81849872 is about 434.1828531454.

The spelling of 81849872 in words is "eighty-one million, eight hundred forty-nine thousand, eight hundred seventy-two".