81861260 has 24 divisors (see below), whose sum is σ = 185132976. Its totient is φ = 30225600.

The previous prime is 81861217. The next prime is 81861281. The reversal of 81861260 is 6216818.

81861260 = T₉ + T₁₀ + ... + T₇₈₈.

It is an unprimeable number.

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, 157166 + ... + 157685.

It is an arithmetic number, because the mean of its divisors is an integer number (7713874).

Almost surely, 2^81861260 is an apocalyptic number.

It is an amenable number.

81861260 is an abundant number, since it is smaller than the sum of its proper divisors (103271716).

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

81861260 is a wasteful number, since it uses less digits than its factorization.

81861260 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 314873 (or 314871 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 81861260 is about 9047.7212600743. The cubic root of 81861260 is about 434.2029885670.

The spelling of 81861260 in words is "eighty-one million, eight hundred sixty-one thousand, two hundred sixty".