1289312649 has 9 divisors (see below), whose sum is σ = 1862496103. Its totient is φ = 859469952.

The previous prime is 1289312639. The next prime is 1289312669. The reversal of 1289312649 is 9462139821.

The square root of 1289312649 is 35907.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 111450249 + 1177862400 = 10557^2 + 34320^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 1289312649 - 2⁹ = 1289312137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1289312639) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 101737 + ... + 113705.

Almost surely, 2^1289312649 is an apocalyptic number.

1289312649 is the 35907-th square number.

1289312649 is the 17954-th centered octagonal number.

It is an amenable number.

1289312649 is a deficient number, since it is larger than the sum of its proper divisors (573183454).

1289312649 is an frugal number, since it uses more digits than its factorization.

1289312649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23944 (or 11972 counting only the distinct ones).

The product of its digits is 186624, while the sum is 45.

The cubic root of 1289312649 is about 1088.3938550400.

Multiplying 1289312649 by its product of digits (186624), we get a square (240616683806976 = 15511824²).

The spelling of 1289312649 in words is "one billion, two hundred eighty-nine million, three hundred twelve thousand, six hundred forty-nine".