1273688021 has 2 divisors, whose sum is σ = 1273688022. Its totient is φ = 1273688020.

The previous prime is 1273688011. The next prime is 1273688027. The reversal of 1273688021 is 1208863721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1055535121 + 218152900 = 32489^2 + 14770^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1273688021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1273688027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 636844010 + 636844011.

It is an arithmetic number, because the mean of its divisors is an integer number (636844011).

Almost surely, 2^1273688021 is an apocalyptic number.

It is an amenable number.

1273688021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1273688021 is an equidigital number, since it uses as much as digits as its factorization.

1273688021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 1273688021 is about 35688.7660335854. The cubic root of 1273688021 is about 1083.9793812997.

The spelling of 1273688021 in words is "one billion, two hundred seventy-three million, six hundred eighty-eight thousand, twenty-one".