8721745 has 8 divisors (see below), whose sum is σ = 10501416. Its totient is φ = 6953856.

The previous prime is 8721737. The next prime is 8721749. The reversal of 8721745 is 5471278.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 859329 + 7862416 = 927^2 + 2804^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 8721745 - 2³ = 8721737 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 8721745.

It is not an unprimeable number, because it can be changed into a prime (8721749) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1222 + ... + 4351.

It is an arithmetic number, because the mean of its divisors is an integer number (1312677).

Almost surely, 2^8721745 is an apocalyptic number.

It is an amenable number.

8721745 is a deficient number, since it is larger than the sum of its proper divisors (1779671).

8721745 is a wasteful number, since it uses less digits than its factorization.

8721745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5891.

The product of its digits is 15680, while the sum is 34.

The square root of 8721745 is about 2953.2600630490. The cubic root of 8721745 is about 205.8422221662.

It can be divided in two parts, 872 and 1745, that multiplied together give a triangular number (1521640 = T₁₇₄₄).

The spelling of 8721745 in words is "eight million, seven hundred twenty-one thousand, seven hundred forty-five".