1287781249 has 2 divisors, whose sum is σ = 1287781250. Its totient is φ = 1287781248.

The previous prime is 1287781241. The next prime is 1287781301. The reversal of 1287781249 is 9421877821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1218359025 + 69422224 = 34905^2 + 8332^2 .

It is a cyclic number.

It is not a de Polignac number, because 1287781249 - 2³ = 1287781241 is a prime.

It is not a weakly prime, because it can be changed into another prime (1287781241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 643890624 + 643890625.

It is an arithmetic number, because the mean of its divisors is an integer number (643890625).

Almost surely, 2^1287781249 is an apocalyptic number.

It is an amenable number.

1287781249 is a deficient number, since it is larger than the sum of its proper divisors (1).

1287781249 is an equidigital number, since it uses as much as digits as its factorization.

1287781249 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 451584, while the sum is 49.

The square root of 1287781249 is about 35885.6691312841. The cubic root of 1287781249 is about 1087.9627657317.

The spelling of 1287781249 in words is "one billion, two hundred eighty-seven million, seven hundred eighty-one thousand, two hundred forty-nine".