1287894749 has 2 divisors, whose sum is σ = 1287894750. Its totient is φ = 1287894748.

The previous prime is 1287894719. The next prime is 1287894791. The reversal of 1287894749 is 9474987821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1170324100 + 117570649 = 34210^2 + 10843^2 .

It is a cyclic number.

It is not a de Polignac number, because 1287894749 - 2⁸ = 1287894493 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1287894719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 643947374 + 643947375.

It is an arithmetic number, because the mean of its divisors is an integer number (643947375).

Almost surely, 2^1287894749 is an apocalyptic number.

It is an amenable number.

1287894749 is a deficient number, since it is larger than the sum of its proper divisors (1).

1287894749 is an equidigital number, since it uses as much as digits as its factorization.

1287894749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8128512, while the sum is 59.

The square root of 1287894749 is about 35887.2505076664. The cubic root of 1287894749 is about 1087.9947277196.

The spelling of 1287894749 in words is "one billion, two hundred eighty-seven million, eight hundred ninety-four thousand, seven hundred forty-nine".