9778561 has 4 divisors (see below), whose sum is σ = 10530772. Its totient is φ = 9026352.

The previous prime is 9778543. The next prime is 9778589. The reversal of 9778561 is 1658779.

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 4648336 + 5130225 = 2156^2 + 2265^2 .

It is a cyclic number.

It is not a de Polignac number, because 9778561 - 2¹⁷ = 9647489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9778061) 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, 376086 + ... + 376111.

It is an arithmetic number, because the mean of its divisors is an integer number (2632693).

Almost surely, 2^9778561 is an apocalyptic number.

It is an amenable number.

9778561 is a deficient number, since it is larger than the sum of its proper divisors (752211).

9778561 is a wasteful number, since it uses less digits than its factorization.

9778561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 752210.

The product of its digits is 105840, while the sum is 43.

The square root of 9778561 is about 3127.0690750286. The cubic root of 9778561 is about 213.8413314204.

The spelling of 9778561 in words is "nine million, seven hundred seventy-eight thousand, five hundred sixty-one".