7872181 has 2 divisors, whose sum is σ = 7872182. Its totient is φ = 7872180.

The previous prime is 7872149. The next prime is 7872191. The reversal of 7872181 is 1812787.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7612081 + 260100 = 2759^2 + 510^2 .

It is a cyclic number.

It is not a de Polignac number, because 7872181 - 2⁵ = 7872149 is a prime.

It is a super-2 number, since 2×7872181² = 123942467393522, which contains 22 as substring.

It is an Ulam number.

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

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7872131) 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 as a sum of consecutive naturals, namely, 3936090 + 3936091.

It is an arithmetic number, because the mean of its divisors is an integer number (3936091).

Almost surely, 2^7872181 is an apocalyptic number.

It is an amenable number.

7872181 is a deficient number, since it is larger than the sum of its proper divisors (1).

7872181 is an equidigital number, since it uses as much as digits as its factorization.

7872181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6272, while the sum is 34.

The square root of 7872181 is about 2805.7407221623. The cubic root of 7872181 is about 198.9291179589.

The spelling of 7872181 in words is "seven million, eight hundred seventy-two thousand, one hundred eighty-one".