81306855 has 64 divisors (see below), whose sum is σ = 167086080. Its totient is φ = 36744192.

The previous prime is 81306821. The next prime is 81306859. The reversal of 81306855 is 55860318.

It is not a de Polignac number, because 81306855 - 2⁷ = 81306727 is a prime.

It is a super-2 number, since 2×81306855² = 13221609339982050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81306859) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 91222 + ... + 92108.

It is an arithmetic number, because the mean of its divisors is an integer number (2610720).

Almost surely, 2^81306855 is an apocalyptic number.

81306855 is an abundant number, since it is smaller than the sum of its proper divisors (85779225).

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

81306855 is a wasteful number, since it uses less digits than its factorization.

81306855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1005 (or 999 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The square root of 81306855 is about 9017.0313851067. The cubic root of 81306855 is about 433.2205548062.

It can be divided in two parts, 81 and 306855, that added together give a triangular number (306936 = T₇₈₃).

The spelling of 81306855 in words is "eighty-one million, three hundred six thousand, eight hundred fifty-five".