172642181 has 2 divisors, whose sum is σ = 172642182. Its totient is φ = 172642180.

The previous prime is 172642121. The next prime is 172642219. The reversal of 172642181 is 181246271.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 139476100 + 33166081 = 11810^2 + 5759^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-172642181 is a prime.

It is a super-2 number, since 2×172642181² = 59610645320873522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172642121) 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, 86321090 + 86321091.

It is an arithmetic number, because the mean of its divisors is an integer number (86321091).

Almost surely, 2^172642181 is an apocalyptic number.

It is an amenable number.

172642181 is a deficient number, since it is larger than the sum of its proper divisors (1).

172642181 is an equidigital number, since it uses as much as digits as its factorization.

172642181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5376, while the sum is 32.

The square root of 172642181 is about 13139.3371598418. The cubic root of 172642181 is about 556.8210410453.

The spelling of 172642181 in words is "one hundred seventy-two million, six hundred forty-two thousand, one hundred eighty-one".