1265537280 has 432 divisors, whose sum is σ = 4883034240. Its totient is φ = 273580032.

The previous prime is 1265537267. The next prime is 1265537281. The reversal of 1265537280 is 827355621.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1265537281) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 14219476 + ... + 14219564.

It is an arithmetic number, because the mean of its divisors is an integer number (11303320).

Almost surely, 2^1265537280 is an apocalyptic number.

1265537280 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 1265537280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2441517120).

1265537280 is an abundant number, since it is smaller than the sum of its proper divisors (3617496960).

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

1265537280 is an equidigital number, since it uses as much as digits as its factorization.

1265537280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166 (or 129 counting only the distinct ones).

The product of its (nonzero) digits is 100800, while the sum is 39.

The square root of 1265537280 is about 35574.3907888807. The cubic root of 1265537280 is about 1081.6621867073.

The spelling of 1265537280 in words is "one billion, two hundred sixty-five million, five hundred thirty-seven thousand, two hundred eighty".