1265540123 has 2 divisors, whose sum is σ = 1265540124. Its totient is φ = 1265540122.

The previous prime is 1265540117. The next prime is 1265540173. The reversal of 1265540123 is 3210455621.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1265540123 is a prime.

It is not a weakly prime, because it can be changed into another prime (1265540173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 632770061 + 632770062.

It is an arithmetic number, because the mean of its divisors is an integer number (632770062).

Almost surely, 2^1265540123 is an apocalyptic number.

1265540123 is a deficient number, since it is larger than the sum of its proper divisors (1).

1265540123 is an equidigital number, since it uses as much as digits as its factorization.

1265540123 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 1265540123 is about 35574.4307473781. The cubic root of 1265540123 is about 1081.6629966830.

Adding to 1265540123 its reverse (3210455621), we get a palindrome (4475995744).

The spelling of 1265540123 in words is "one billion, two hundred sixty-five million, five hundred forty thousand, one hundred twenty-three".