1281439723 has 2 divisors, whose sum is σ = 1281439724. Its totient is φ = 1281439722.

The previous prime is 1281439717. The next prime is 1281439727. The reversal of 1281439723 is 3279341821.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1281439723 is a prime.

It is not a weakly prime, because it can be changed into another prime (1281439727) 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, 640719861 + 640719862.

It is an arithmetic number, because the mean of its divisors is an integer number (640719862).

Almost surely, 2^1281439723 is an apocalyptic number.

1281439723 is a deficient number, since it is larger than the sum of its proper divisors (1).

1281439723 is an equidigital number, since it uses as much as digits as its factorization.

1281439723 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 40.

The square root of 1281439723 is about 35797.2027259114. The cubic root of 1281439723 is about 1086.1739784262.

The spelling of 1281439723 in words is "one billion, two hundred eighty-one million, four hundred thirty-nine thousand, seven hundred twenty-three".