81351884 has 6 divisors (see below), whose sum is σ = 142365804. Its totient is φ = 40675940.

The previous prime is 81351883. The next prime is 81351899. The reversal of 81351884 is 48815318.

It is not an unprimeable number, because it can be changed into a prime (81351883) by changing a digit.

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 as a sum of consecutive naturals, namely, 10168982 + ... + 10168989.

It is an arithmetic number, because the mean of its divisors is an integer number (23727634).

Almost surely, 2^81351884 is an apocalyptic number.

It is an amenable number.

81351884 is a deficient number, since it is larger than the sum of its proper divisors (61013920).

81351884 is a wasteful number, since it uses less digits than its factorization.

81351884 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20337975 (or 20337973 counting only the distinct ones).

The product of its digits is 30720, while the sum is 38.

The square root of 81351884 is about 9019.5279255624. The cubic root of 81351884 is about 433.3005148058.

The spelling of 81351884 in words is "eighty-one million, three hundred fifty-one thousand, eight hundred eighty-four".