81872205 has 8 divisors (see below), whose sum is σ = 130995552. Its totient is φ = 43665168.

The previous prime is 81872143. The next prime is 81872207. The reversal of 81872205 is 50227818.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81872205 - 2¹⁵ = 81839437 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81872207) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2729059 + ... + 2729088.

It is an arithmetic number, because the mean of its divisors is an integer number (16374444).

Almost surely, 2^81872205 is an apocalyptic number.

It is an amenable number.

81872205 is a deficient number, since it is larger than the sum of its proper divisors (49123347).

81872205 is a wasteful number, since it uses less digits than its factorization.

81872205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5458155.

The product of its (nonzero) digits is 8960, while the sum is 33.

The square root of 81872205 is about 9048.3260882884. The cubic root of 81872205 is about 434.2223389489. Note that the first 3 decimals are identical.

The spelling of 81872205 in words is "eighty-one million, eight hundred seventy-two thousand, two hundred five".