81147885 has 96 divisors (see below), whose sum is σ = 170760960. Its totient is φ = 32108544.

The previous prime is 81147883. The next prime is 81147889. The reversal of 81147885 is 58874118.

It is not a de Polignac number, because 81147885 - 2¹ = 81147883 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81147883) 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 95 ways as a sum of consecutive naturals, for example, 301531 + ... + 301799.

It is an arithmetic number, because the mean of its divisors is an integer number (1778760).

Almost surely, 2^81147885 is an apocalyptic number.

81147885 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

81147885 is an abundant number, since it is smaller than the sum of its proper divisors (89613075).

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

81147885 is a wasteful number, since it uses less digits than its factorization.

81147885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 327 (or 314 counting only the distinct ones).

The product of its digits is 71680, while the sum is 42.

The square root of 81147885 is about 9008.2120867573. The cubic root of 81147885 is about 432.9380283847.

The spelling of 81147885 in words is "eighty-one million, one hundred forty-seven thousand, eight hundred eighty-five".