1265540656 has 20 divisors (see below), whose sum is σ = 2596219992. Its totient is φ = 595548416.

The previous prime is 1265540609. The next prime is 1265540669. The reversal of 1265540656 is 6560455621.

It is a super-4 number, since 4×1265540656⁴ (a number of 38 digits) contains 4444 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2326090 + ... + 2326633.

Almost surely, 2^1265540656 is an apocalyptic number.

1265540656 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1265540656 is an abundant number, since it is smaller than the sum of its proper divisors (1330679336).

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

1265540656 is a wasteful number, since it uses less digits than its factorization.

1265540656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4652748 (or 4652742 counting only the distinct ones).

The product of its (nonzero) digits is 216000, while the sum is 40.

The square root of 1265540656 is about 35574.4382387129. The cubic root of 1265540656 is about 1081.6631485355.

The spelling of 1265540656 in words is "one billion, two hundred sixty-five million, five hundred forty thousand, six hundred fifty-six".