1266221320 has 128 divisors (see below), whose sum is σ = 3518403840. Its totient is φ = 399375360.

The previous prime is 1266221311. The next prime is 1266221329. The reversal of 1266221320 is 231226621.

It is an interprime number because it is at equal distance from previous prime (1266221311) and next prime (1266221329).

It is not an unprimeable number, because it can be changed into a prime (1266221329) 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 31 ways as a sum of consecutive naturals, for example, 1968919 + ... + 1969561.

It is an arithmetic number, because the mean of its divisors is an integer number (27487530).

Almost surely, 2^1266221320 is an apocalyptic number.

1266221320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1266221320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1759201920).

1266221320 is an abundant number, since it is smaller than the sum of its proper divisors (2252182520).

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

1266221320 is a wasteful number, since it uses less digits than its factorization.

1266221320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1215 (or 1211 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 1266221320 is about 35584.0037095322. The cubic root of 1266221320 is about 1081.8570359478.

Adding to 1266221320 its reverse (231226621), we get a palindrome (1497447941).

The spelling of 1266221320 in words is "one billion, two hundred sixty-six million, two hundred twenty-one thousand, three hundred twenty".