1287850561 has 2 divisors, whose sum is σ = 1287850562. Its totient is φ = 1287850560.

The previous prime is 1287850537. The next prime is 1287850573. The reversal of 1287850561 is 1650587821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 922276161 + 365574400 = 30369^2 + 19120^2 .

It is an emirp because it is prime and its reverse (1650587821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1287850561 - 2⁹ = 1287850049 is a prime.

It is not a weakly prime, because it can be changed into another prime (1287851561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 643925280 + 643925281.

It is an arithmetic number, because the mean of its divisors is an integer number (643925281).

Almost surely, 2^1287850561 is an apocalyptic number.

It is an amenable number.

1287850561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1287850561 is an equidigital number, since it uses as much as digits as its factorization.

1287850561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 134400, while the sum is 43.

The square root of 1287850561 is about 35886.6348519891. The cubic root of 1287850561 is about 1087.9822844510.

The spelling of 1287850561 in words is "one billion, two hundred eighty-seven million, eight hundred fifty thousand, five hundred sixty-one".