1288421 has 2 divisors, whose sum is σ = 1288422. Its totient is φ = 1288420.

The previous prime is 1288393. The next prime is 1288423. The reversal of 1288421 is 1248821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1288225 + 196 = 1135^2 + 14^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1288421 is a prime.

Together with 1288423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1288423) 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, 644210 + 644211.

It is an arithmetic number, because the mean of its divisors is an integer number (644211).

2^1288421 is an apocalyptic number.

It is an amenable number.

1288421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1288421 is an equidigital number, since it uses as much as digits as its factorization.

1288421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1024, while the sum is 26.

The square root of 1288421 is about 1135.0863403283. The cubic root of 1288421 is about 108.8142897267.

The spelling of 1288421 in words is "one million, two hundred eighty-eight thousand, four hundred twenty-one".