1273909921 has 2 divisors, whose sum is σ = 1273909922. Its totient is φ = 1273909920.

The previous prime is 1273909867. The next prime is 1273909951. The reversal of 1273909921 is 1299093721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1153349521 + 120560400 = 33961^2 + 10980^2 .

It is an emirp because it is prime and its reverse (1299093721) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1273909921 - 2¹⁵ = 1273877153 is a prime.

It is not a weakly prime, because it can be changed into another prime (1273909951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 636954960 + 636954961.

It is an arithmetic number, because the mean of its divisors is an integer number (636954961).

Almost surely, 2^1273909921 is an apocalyptic number.

It is an amenable number.

1273909921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1273909921 is an equidigital number, since it uses as much as digits as its factorization.

1273909921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 61236, while the sum is 43.

The square root of 1273909921 is about 35691.8747196053. The cubic root of 1273909921 is about 1084.0423273936.

The spelling of 1273909921 in words is "one billion, two hundred seventy-three million, nine hundred nine thousand, nine hundred twenty-one".