1272236545 has 4 divisors (see below), whose sum is σ = 1526683860. Its totient is φ = 1017789232.

The previous prime is 1272236509. The next prime is 1272236549. The reversal of 1272236545 is 5456322721.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5456322721 = 103 ⋅52974007.

It can be written as a sum of positive squares in 2 ways, for example, as 827827984 + 444408561 = 28772^2 + 21081^2 .

It is a cyclic number.

It is not a de Polignac number, because 1272236545 - 2⁷ = 1272236417 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1272236549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127223650 + ... + 127223659.

It is an arithmetic number, because the mean of its divisors is an integer number (381670965).

Almost surely, 2^1272236545 is an apocalyptic number.

It is an amenable number.

1272236545 is a deficient number, since it is larger than the sum of its proper divisors (254447315).

1272236545 is an equidigital number, since it uses as much as digits as its factorization.

1272236545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 254447314.

The product of its digits is 100800, while the sum is 37.

The square root of 1272236545 is about 35668.4250423256. The cubic root of 1272236545 is about 1083.5674625063.

The spelling of 1272236545 in words is "one billion, two hundred seventy-two million, two hundred thirty-six thousand, five hundred forty-five".