1716921 has 6 divisors (see below), whose sum is σ = 2480010. Its totient is φ = 1144608.

The previous prime is 1716917. The next prime is 1716931. The reversal of 1716921 is 1296171.

It can be written as a sum of positive squares in only one way, i.e., 1527696 + 189225 = 1236^2 + 435^2 .

It is not a de Polignac number, because 1716921 - 2² = 1716917 is a prime.

It is an Ulam number.

1716921 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1716901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 95376 + ... + 95393.

It is an arithmetic number, because the mean of its divisors is an integer number (413335).

2^1716921 is an apocalyptic number.

It is an amenable number.

1716921 is a deficient number, since it is larger than the sum of its proper divisors (763089).

1716921 is a wasteful number, since it uses less digits than its factorization.

1716921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190775 (or 190772 counting only the distinct ones).

The product of its digits is 756, while the sum is 27.

The square root of 1716921 is about 1310.3133213091. The cubic root of 1716921 is about 119.7429916154.

It can be divided in two parts, 171 and 6921, that multiplied together give a triangular number (1183491 = T₁₅₃₈).

The spelling of 1716921 in words is "one million, seven hundred sixteen thousand, nine hundred twenty-one".