1272918221 has 2 divisors, whose sum is σ = 1272918222. Its totient is φ = 1272918220.

The previous prime is 1272918169. The next prime is 1272918307. The reversal of 1272918221 is 1228192721.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1148260996 + 124657225 = 33886^2 + 11165^2 .

It is a cyclic number.

It is not a de Polignac number, because 1272918221 - 2¹⁰ = 1272917197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1272918421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 636459110 + 636459111.

It is an arithmetic number, because the mean of its divisors is an integer number (636459111).

Almost surely, 2^1272918221 is an apocalyptic number.

It is an amenable number.

1272918221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1272918221 is an equidigital number, since it uses as much as digits as its factorization.

1272918221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 35.

The square root of 1272918221 is about 35677.9794971632. The cubic root of 1272918221 is about 1083.7609564107.

The spelling of 1272918221 in words is "one billion, two hundred seventy-two million, nine hundred eighteen thousand, two hundred twenty-one".