1265660400 has 60 divisors (see below), whose sum is σ = 4054335992. Its totient is φ = 337509120.

The previous prime is 1265660393. The next prime is 1265660401. The reversal of 1265660400 is 40665621.

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1265660401) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 526159 + ... + 528558.

Almost surely, 2^1265660400 is an apocalyptic number.

1265660400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1265660400 is an abundant number, since it is smaller than the sum of its proper divisors (2788675592).

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

1265660400 is a wasteful number, since it uses less digits than its factorization.

1265660400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1054738 (or 1054727 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 1265660400 is about 35576.1212051005. The cubic root of 1265660400 is about 1081.6972627002.

The spelling of 1265660400 in words is "one billion, two hundred sixty-five million, six hundred sixty thousand, four hundred".