649978289 has 8 divisors (see below), whose sum is σ = 704998728. Its totient is φ = 596823040.

The previous prime is 649978283. The next prime is 649978291. The reversal of 649978289 is 982879946.

It can be written as a sum of positive squares in 4 ways, for example, as 6848689 + 643129600 = 2617^2 + 25360^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 649978289 - 2²⁴ = 633201073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (649978283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 465572 + ... + 466965.

It is an arithmetic number, because the mean of its divisors is an integer number (88124841).

Almost surely, 2^649978289 is an apocalyptic number.

It is an amenable number.

649978289 is a deficient number, since it is larger than the sum of its proper divisors (55020439).

649978289 is a wasteful number, since it uses less digits than its factorization.

649978289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 932595.

The product of its digits is 15676416, while the sum is 62.

The square root of 649978289 is about 25494.6717766674. The cubic root of 649978289 is about 866.2294606606.

The spelling of 649978289 in words is "six hundred forty-nine million, nine hundred seventy-eight thousand, two hundred eighty-nine".