81788930 has 16 divisors (see below), whose sum is σ = 150353280. Its totient is φ = 32019312.

The previous prime is 81788929. The next prime is 81788963. The reversal of 81788930 is 3988718.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 86540 + ... + 87479.

It is an arithmetic number, because the mean of its divisors is an integer number (9397080).

Almost surely, 2^81788930 is an apocalyptic number.

81788930 is a deficient number, since it is larger than the sum of its proper divisors (68564350).

81788930 is a wasteful number, since it uses less digits than its factorization.

81788930 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174073.

The product of its (nonzero) digits is 96768, while the sum is 44.

The square root of 81788930 is about 9043.7232376936. The cubic root of 81788930 is about 434.0750682440.

The spelling of 81788930 in words is "eighty-one million, seven hundred eighty-eight thousand, nine hundred thirty".