81872307 has 24 divisors (see below), whose sum is σ = 133464240. Its totient is φ = 47906880.

The previous prime is 81872303. The next prime is 81872321. The reversal of 81872307 is 70327818.

It is not a de Polignac number, because 81872307 - 2² = 81872303 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (81872303) 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 23 ways as a sum of consecutive naturals, for example, 11388 + ... + 17129.

It is an arithmetic number, because the mean of its divisors is an integer number (5561010).

Almost surely, 2^81872307 is an apocalyptic number.

81872307 is a gapful number since it is divisible by the number (87) formed by its first and last digit.

81872307 is a deficient number, since it is larger than the sum of its proper divisors (51591933).

81872307 is a wasteful number, since it uses less digits than its factorization.

81872307 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28563 (or 28560 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The square root of 81872307 is about 9048.3317246883. The cubic root of 81872307 is about 434.2225192732. Note that the first 3 decimals are identical.

The spelling of 81872307 in words is "eighty-one million, eight hundred seventy-two thousand, three hundred seven".