1265721072 has 160 divisors (see below), whose sum is σ = 4208492544. Its totient is φ = 318124800.

The previous prime is 1265721071. The next prime is 1265721091. The reversal of 1265721072 is 2701275621.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1265721071) 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 in 31 ways as a sum of consecutive naturals, for example, 109053 + ... + 120099.

Almost surely, 2^1265721072 is an apocalyptic number.

1265721072 is a gapful number since it is divisible by the number (12) 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 1265721072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2104246272).

1265721072 is an abundant number, since it is smaller than the sum of its proper divisors (2942771472).

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

1265721072 is a wasteful number, since it uses less digits than its factorization.

1265721072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11107 (or 11101 counting only the distinct ones).

The product of its (nonzero) digits is 11760, while the sum is 33.

The square root of 1265721072 is about 35576.9739016685. The cubic root of 1265721072 is about 1081.7145468752.

Adding to 1265721072 its reverse (2701275621), we get a palindrome (3966996693).

The spelling of 1265721072 in words is "one billion, two hundred sixty-five million, seven hundred twenty-one thousand, seventy-two".