8780921 has 4 divisors (see below), whose sum is σ = 8826612. Its totient is φ = 8735232.

The previous prime is 8780909. The next prime is 8780923. The reversal of 8780921 is 1290878.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1784896 + 6996025 = 1336^2 + 2645^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8780921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8780923) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22556 + ... + 22941.

It is an arithmetic number, because the mean of its divisors is an integer number (2206653).

Almost surely, 2^8780921 is an apocalyptic number.

It is an amenable number.

8780921 is a deficient number, since it is larger than the sum of its proper divisors (45691).

8780921 is a wasteful number, since it uses less digits than its factorization.

8780921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45690.

The product of its (nonzero) digits is 8064, while the sum is 35.

The square root of 8780921 is about 2963.2618851529. The cubic root of 8780921 is about 206.3067115552.

The spelling of 8780921 in words is "eight million, seven hundred eighty thousand, nine hundred twenty-one".