1286713721 has 2 divisors, whose sum is σ = 1286713722. Its totient is φ = 1286713720.

The previous prime is 1286713693. The next prime is 1286713723. The reversal of 1286713721 is 1273176821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1015123321 + 271590400 = 31861^2 + 16480^2 .

It is a cyclic number.

It is not a de Polignac number, because 1286713721 - 2¹⁰ = 1286712697 is a prime.

Together with 1286713723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1286713723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 643356860 + 643356861.

It is an arithmetic number, because the mean of its divisors is an integer number (643356861).

Almost surely, 2^1286713721 is an apocalyptic number.

It is an amenable number.

1286713721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1286713721 is an equidigital number, since it uses as much as digits as its factorization.

1286713721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28224, while the sum is 38.

The square root of 1286713721 is about 35870.7920319583. The cubic root of 1286713721 is about 1087.6620542578.

The spelling of 1286713721 in words is "one billion, two hundred eighty-six million, seven hundred thirteen thousand, seven hundred twenty-one".