81849906 has 16 divisors (see below), whose sum is σ = 181888800. Its totient is φ = 27283284.

The previous prime is 81849881. The next prime is 81849959. The reversal of 81849906 is 60994818.

It is a super-2 number, since 2×81849906² = 13398814224417672, which contains 22 as substring.

It is a Curzon 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 7 ways as a sum of consecutive naturals, for example, 757816 + ... + 757923.

It is an arithmetic number, because the mean of its divisors is an integer number (11368050).

Almost surely, 2^81849906 is an apocalyptic number.

81849906 is an abundant number, since it is smaller than the sum of its proper divisors (100038894).

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

81849906 is a wasteful number, since it uses less digits than its factorization.

81849906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1515750 (or 1515744 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 45.

The square root of 81849906 is about 9047.0937875099. The cubic root of 81849906 is about 434.1829132645.

The spelling of 81849906 in words is "eighty-one million, eight hundred forty-nine thousand, nine hundred six".