8780509921 has 2 divisors, whose sum is σ = 8780509922. Its totient is φ = 8780509920.

The previous prime is 8780509909. The next prime is 8780509931. The reversal of 8780509921 is 1299050878.

8780509921 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7803072225 + 977437696 = 88335^2 + 31264^2 .

It is a cyclic number.

It is not a de Polignac number, because 8780509921 - 2¹³ = 8780501729 is a prime.

It is not a weakly prime, because it can be changed into another prime (8780509931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4390254960 + 4390254961.

It is an arithmetic number, because the mean of its divisors is an integer number (4390254961).

Almost surely, 2^8780509921 is an apocalyptic number.

It is an amenable number.

8780509921 is a deficient number, since it is larger than the sum of its proper divisors (1).

8780509921 is an equidigital number, since it uses as much as digits as its factorization.

8780509921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 362880, while the sum is 49.

The square root of 8780509921 is about 93704.3751433197. The cubic root of 8780509921 is about 2063.0349208725.

The spelling of 8780509921 in words is "eight billion, seven hundred eighty million, five hundred nine thousand, nine hundred twenty-one".