8647780921 has 16 divisors (see below), whose sum is σ = 9367722000. Its totient is φ = 7935787008.

The previous prime is 8647780913. The next prime is 8647780931. The reversal of 8647780921 is 1290877468.

It can be written as a sum of positive squares in 8 ways, for example, as 47073321 + 8600707600 = 6861^2 + 92740^2 .

It is a cyclic number.

It is not a de Polignac number, because 8647780921 - 2³ = 8647780913 is a prime.

It is a super-2 number, since 2×8647780921² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (8647780931) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1898755 + ... + 1903303.

It is an arithmetic number, because the mean of its divisors is an integer number (585482625).

Almost surely, 2^8647780921 is an apocalyptic number.

It is an amenable number.

8647780921 is a deficient number, since it is larger than the sum of its proper divisors (719941079).

8647780921 is a wasteful number, since it uses less digits than its factorization.

8647780921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5388.

The product of its (nonzero) digits is 1354752, while the sum is 52.

The square root of 8647780921 is about 92993.4455808580. The cubic root of 8647780921 is about 2052.5869321078.

The spelling of 8647780921 in words is "eight billion, six hundred forty-seven million, seven hundred eighty thousand, nine hundred twenty-one".