1243220265 has 128 divisors (see below), whose sum is σ = 2694021120. Its totient is φ = 531615744.

The previous prime is 1243220243. The next prime is 1243220269. The reversal of 1243220265 is 5620223421.

It is a happy number.

It is not a de Polignac number, because 1243220265 - 2⁶ = 1243220201 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (1243220269) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1020937 + ... + 1022153.

It is an arithmetic number, because the mean of its divisors is an integer number (21047040).

Almost surely, 2^1243220265 is an apocalyptic number.

1243220265 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1243220265 is an abundant number, since it is smaller than the sum of its proper divisors (1450800855).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1243220265 is a wasteful number, since it uses less digits than its factorization.

1243220265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1308 (or 1302 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 1243220265 is about 35259.3287655905. The cubic root of 1243220265 is about 1075.2662805297.

Adding to 1243220265 its reverse (5620223421), we get a palindrome (6863443686).

The spelling of 1243220265 in words is "one billion, two hundred forty-three million, two hundred twenty thousand, two hundred sixty-five".