172409179861 has 2 divisors, whose sum is σ = 172409179862. Its totient is φ = 172409179860.

The previous prime is 172409179841. The next prime is 172409179931. The reversal of 172409179861 is 168971904271.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 132700646961 + 39708532900 = 364281^2 + 199270^2 .

It is an emirp because it is prime and its reverse (168971904271) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-172409179861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172409179841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86204589930 + 86204589931.

It is an arithmetic number, because the mean of its divisors is an integer number (86204589931).

Almost surely, 2^172409179861 is an apocalyptic number.

It is an amenable number.

172409179861 is a deficient number, since it is larger than the sum of its proper divisors (1).

172409179861 is an equidigital number, since it uses as much as digits as its factorization.

172409179861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1524096, while the sum is 55.

The spelling of 172409179861 in words is "one hundred seventy-two billion, four hundred nine million, one hundred seventy-nine thousand, eight hundred sixty-one".