1287638777 has 2 divisors, whose sum is σ = 1287638778. Its totient is φ = 1287638776.

The previous prime is 1287638767. The next prime is 1287638783. The reversal of 1287638777 is 7778367821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 952895161 + 334743616 = 30869^2 + 18296^2 .

It is a cyclic number.

It is not a de Polignac number, because 1287638777 - 2¹⁸ = 1287376633 is a prime.

It is not a weakly prime, because it can be changed into another prime (1287638717) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 643819388 + 643819389.

It is an arithmetic number, because the mean of its divisors is an integer number (643819389).

Almost surely, 2^1287638777 is an apocalyptic number.

It is an amenable number.

1287638777 is a deficient number, since it is larger than the sum of its proper divisors (1).

1287638777 is an equidigital number, since it uses as much as digits as its factorization.

1287638777 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5531904, while the sum is 56.

The square root of 1287638777 is about 35883.6839942612. The cubic root of 1287638777 is about 1087.9226424711.

The spelling of 1287638777 in words is "one billion, two hundred eighty-seven million, six hundred thirty-eight thousand, seven hundred seventy-seven".