171861643 has 2 divisors, whose sum is σ = 171861644. Its totient is φ = 171861642.

The previous prime is 171861629. The next prime is 171861661. The reversal of 171861643 is 346168171.

It is a weak prime.

It is an emirp because it is prime and its reverse (346168171) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 171861643 - 2¹⁷ = 171730571 is a prime.

It is not a weakly prime, because it can be changed into another prime (171861623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 85930821 + 85930822.

It is an arithmetic number, because the mean of its divisors is an integer number (85930822).

Almost surely, 2^171861643 is an apocalyptic number.

171861643 is a deficient number, since it is larger than the sum of its proper divisors (1).

171861643 is an equidigital number, since it uses as much as digits as its factorization.

171861643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24192, while the sum is 37.

The square root of 171861643 is about 13109.6011762372. The cubic root of 171861643 is about 555.9806195046.

The spelling of 171861643 in words is "one hundred seventy-one million, eight hundred sixty-one thousand, six hundred forty-three".