1272156817 has 2 divisors, whose sum is σ = 1272156818. Its totient is φ = 1272156816.

The previous prime is 1272156791. The next prime is 1272156877. The reversal of 1272156817 is 7186512721.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1182740881 + 89415936 = 34391^2 + 9456^2 .

It is a cyclic number.

It is not a de Polignac number, because 1272156817 - 2¹⁹ = 1271632529 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1272156817.

It is not a weakly prime, because it can be changed into another prime (1272156877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 636078408 + 636078409.

It is an arithmetic number, because the mean of its divisors is an integer number (636078409).

Almost surely, 2^1272156817 is an apocalyptic number.

It is an amenable number.

1272156817 is a deficient number, since it is larger than the sum of its proper divisors (1).

1272156817 is an equidigital number, since it uses as much as digits as its factorization.

1272156817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 47040, while the sum is 40.

The square root of 1272156817 is about 35667.3073976716. The cubic root of 1272156817 is about 1083.5448271792.

The spelling of 1272156817 in words is "one billion, two hundred seventy-two million, one hundred fifty-six thousand, eight hundred seventeen".