1287445021 has 2 divisors, whose sum is σ = 1287445022. Its totient is φ = 1287445020.

The previous prime is 1287444979. The next prime is 1287445057. The reversal of 1287445021 is 1205447821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1150227225 + 137217796 = 33915^2 + 11714^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1287445021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1287445421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 643722510 + 643722511.

It is an arithmetic number, because the mean of its divisors is an integer number (643722511).

Almost surely, 2^1287445021 is an apocalyptic number.

It is an amenable number.

1287445021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1287445021 is an equidigital number, since it uses as much as digits as its factorization.

1287445021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17920, while the sum is 34.

The square root of 1287445021 is about 35880.9841141516. The cubic root of 1287445021 is about 1087.8680717543.

The spelling of 1287445021 in words is "one billion, two hundred eighty-seven million, four hundred forty-five thousand, twenty-one".