123171721 has 2 divisors, whose sum is σ = 123171722. Its totient is φ = 123171720.

The previous prime is 123171709. The next prime is 123171731. The reversal of 123171721 is 127171321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76317696 + 46854025 = 8736^2 + 6845^2 .

It is a cyclic number.

It is not a de Polignac number, because 123171721 - 2¹⁹ = 122647433 is a prime.

It is not a weakly prime, because it can be changed into another prime (123171701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61585860 + 61585861.

It is an arithmetic number, because the mean of its divisors is an integer number (61585861).

Almost surely, 2^123171721 is an apocalyptic number.

It is an amenable number.

123171721 is a deficient number, since it is larger than the sum of its proper divisors (1).

123171721 is an equidigital number, since it uses as much as digits as its factorization.

123171721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 588, while the sum is 25.

The square root of 123171721 is about 11098.2755867747. The cubic root of 123171721 is about 497.5503123280.

The spelling of 123171721 in words is "one hundred twenty-three million, one hundred seventy-one thousand, seven hundred twenty-one".