1265721200 has 30 divisors (see below), whose sum is σ = 3040896144. Its totient is φ = 506288320.

The previous prime is 1265721181. The next prime is 1265721203. The reversal of 1265721200 is 21275621.

It is a super-2 number, since 2×1265721200² = 3204100312258880000, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1265721200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1265721203) 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 5 ways as a sum of consecutive naturals, for example, 1581752 + ... + 1582551.

Almost surely, 2^1265721200 is an apocalyptic number.

1265721200 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1265721200 is an abundant number, since it is smaller than the sum of its proper divisors (1775174944).

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

1265721200 is a wasteful number, since it uses less digits than its factorization.

1265721200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3164321 (or 3164310 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 1265721200 is about 35576.9757005848. The cubic root of 1265721200 is about 1081.7145833391.

Adding to 1265721200 its reverse (21275621), we get a palindrome (1286996821).

The spelling of 1265721200 in words is "one billion, two hundred sixty-five million, seven hundred twenty-one thousand, two hundred".