1281521 has 2 divisors, whose sum is σ = 1281522. Its totient is φ = 1281520.

The previous prime is 1281503. The next prime is 1281523. The reversal of 1281521 is 1251821.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 703921 + 577600 = 839^2 + 760^2 .

It is a cyclic number.

It is not a de Polignac number, because 1281521 - 2⁶ = 1281457 is a prime.

Together with 1281523, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 1281493 and 1281502.

It is not a weakly prime, because it can be changed into another prime (1281523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 640760 + 640761.

It is an arithmetic number, because the mean of its divisors is an integer number (640761).

2^1281521 is an apocalyptic number.

It is an amenable number.

1281521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1281521 is an equidigital number, since it uses as much as digits as its factorization.

1281521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 160, while the sum is 20.

The square root of 1281521 is about 1132.0428437122. The cubic root of 1281521 is about 108.6196941945.

The spelling of 1281521 in words is "one million, two hundred eighty-one thousand, five hundred twenty-one".