81745388 has 12 divisors (see below), whose sum is σ = 147669312. Its totient is φ = 39554160.

The previous prime is 81745387. The next prime is 81745393. The reversal of 81745388 is 88354718.

It is not an unprimeable number, because it can be changed into a prime (81745387) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 329495 + ... + 329742.

It is an arithmetic number, because the mean of its divisors is an integer number (12305776).

Almost surely, 2^81745388 is an apocalyptic number.

It is an amenable number.

81745388 is a deficient number, since it is larger than the sum of its proper divisors (65923924).

81745388 is a wasteful number, since it uses less digits than its factorization.

81745388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 659272 (or 659270 counting only the distinct ones).

The product of its digits is 215040, while the sum is 44.

The square root of 81745388 is about 9041.3156122325. The cubic root of 81745388 is about 433.9980250075.

The spelling of 81745388 in words is "eighty-one million, seven hundred forty-five thousand, three hundred eighty-eight".