172805639 has 2 divisors, whose sum is σ = 172805640. Its totient is φ = 172805638.

The previous prime is 172805623. The next prime is 172805669. The reversal of 172805639 is 936508271.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 172805639 - 2⁴ = 172805623 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 172805596 and 172805605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172805609) 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, 86402819 + 86402820.

It is an arithmetic number, because the mean of its divisors is an integer number (86402820).

Almost surely, 2^172805639 is an apocalyptic number.

172805639 is a deficient number, since it is larger than the sum of its proper divisors (1).

172805639 is an equidigital number, since it uses as much as digits as its factorization.

172805639 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 90720, while the sum is 41.

The square root of 172805639 is about 13145.5558650062. Note that the first 3 decimals coincide. The cubic root of 172805639 is about 556.9967187453.

The spelling of 172805639 in words is "one hundred seventy-two million, eight hundred five thousand, six hundred thirty-nine".