1281136421 has 2 divisors, whose sum is σ = 1281136422. Its totient is φ = 1281136420.

The previous prime is 1281136369. The next prime is 1281136447. The reversal of 1281136421 is 1246311821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 989102500 + 292033921 = 31450^2 + 17089^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1281136421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1281136321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 640568210 + 640568211.

It is an arithmetic number, because the mean of its divisors is an integer number (640568211).

Almost surely, 2^1281136421 is an apocalyptic number.

It is an amenable number.

1281136421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1281136421 is an equidigital number, since it uses as much as digits as its factorization.

1281136421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2304, while the sum is 29.

The square root of 1281136421 is about 35792.9660827375. The cubic root of 1281136421 is about 1086.0882767141.

The spelling of 1281136421 in words is "one billion, two hundred eighty-one million, one hundred thirty-six thousand, four hundred twenty-one".