81625878 has 12 divisors (see below), whose sum is σ = 176856108. Its totient is φ = 27208620.

The previous prime is 81625853. The next prime is 81625879. The reversal of 81625878 is 87852618.

81625878 is a `hidden beast` number, since 8 + 1 + 62 + 587 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81625879) 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 in 5 ways as a sum of consecutive naturals, for example, 2267368 + ... + 2267403.

It is an arithmetic number, because the mean of its divisors is an integer number (14738009).

Almost surely, 2^81625878 is an apocalyptic number.

81625878 is an abundant number, since it is smaller than the sum of its proper divisors (95230230).

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

81625878 is a wasteful number, since it uses less digits than its factorization.

81625878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4534779 (or 4534776 counting only the distinct ones).

The product of its digits is 215040, while the sum is 45.

The square root of 81625878 is about 9034.7040903396. The cubic root of 81625878 is about 433.7864232605.

The spelling of 81625878 in words is "eighty-one million, six hundred twenty-five thousand, eight hundred seventy-eight".