72100081 has 2 divisors, whose sum is σ = 72100082. Its totient is φ = 72100080.

The previous prime is 72100069. The next prime is 72100097. The reversal of 72100081 is 18000127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 70560000 + 1540081 = 8400^2 + 1241^2 .

It is a cyclic number.

It is not a de Polignac number, because 72100081 - 2²⁵ = 38545649 is a prime.

It is a super-2 number, since 2×72100081² = 10396843360413122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (72100031) 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 as a sum of consecutive naturals, namely, 36050040 + 36050041.

It is an arithmetic number, because the mean of its divisors is an integer number (36050041).

Almost surely, 2^72100081 is an apocalyptic number.

It is an amenable number.

72100081 is a deficient number, since it is larger than the sum of its proper divisors (1).

72100081 is an equidigital number, since it uses as much as digits as its factorization.

72100081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112, while the sum is 19.

The square root of 72100081 is about 8491.1766557998. The cubic root of 72100081 is about 416.2094317282.

The spelling of 72100081 in words is "seventy-two million, one hundred thousand, eighty-one".