81849904 has 10 divisors (see below), whose sum is σ = 158584220. Its totient is φ = 40924944.

The previous prime is 81849881. The next prime is 81849959. The reversal of 81849904 is 40994818.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2557794 + ... + 2557825.

It is an arithmetic number, because the mean of its divisors is an integer number (15858422).

Almost surely, 2^81849904 is an apocalyptic number.

It is an amenable number.

81849904 is a deficient number, since it is larger than the sum of its proper divisors (76734316).

81849904 is a wasteful number, since it uses less digits than its factorization.

81849904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5115627 (or 5115621 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 43.

The square root of 81849904 is about 9047.0936769772. The cubic root of 81849904 is about 434.1829097280.

The spelling of 81849904 in words is "eighty-one million, eight hundred forty-nine thousand, nine hundred four".