81812620 has 24 divisors (see below), whose sum is σ = 173048400. Its totient is φ = 32488512.

The previous prime is 81812603. The next prime is 81812623. The reversal of 81812620 is 2621818.

It is not an unprimeable number, because it can be changed into a prime (81812623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11935 + ... + 17494.

It is an arithmetic number, because the mean of its divisors is an integer number (7210350).

Almost surely, 2^81812620 is an apocalyptic number.

It is an amenable number.

81812620 is an abundant number, since it is smaller than the sum of its proper divisors (91235780).

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

81812620 is a wasteful number, since it uses less digits than its factorization.

81812620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29577 (or 29575 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 81812620 is about 9045.0328910403. The cubic root of 81812620 is about 434.1169738567.

It can be divided in two parts, 8181 and 2620, that added together give a palindrome (10801).

The spelling of 81812620 in words is "eighty-one million, eight hundred twelve thousand, six hundred twenty".