864778489 has 2 divisors, whose sum is σ = 864778490. Its totient is φ = 864778488.

The previous prime is 864778487. The next prime is 864778501. The reversal of 864778489 is 984877468.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 835672464 + 29106025 = 28908^2 + 5395^2 .

It is a cyclic number.

It is not a de Polignac number, because 864778489 - 2¹ = 864778487 is a prime.

Together with 864778487, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (864778487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 432389244 + 432389245.

It is an arithmetic number, because the mean of its divisors is an integer number (432389245).

Almost surely, 2^864778489 is an apocalyptic number.

It is an amenable number.

864778489 is a deficient number, since it is larger than the sum of its proper divisors (1).

864778489 is an equidigital number, since it uses as much as digits as its factorization.

864778489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21676032, while the sum is 61.

The square root of 864778489 is about 29407.1162986104. The cubic root of 864778489 is about 952.7266041640.

The spelling of 864778489 in words is "eight hundred sixty-four million, seven hundred seventy-eight thousand, four hundred eighty-nine".