1265180861520 has 120 divisors (see below), whose sum is σ = 4249677102216. Its totient is φ = 337319783424.

The previous prime is 1265180861473. The next prime is 1265180861531. The reversal of 1265180861520 is 251680815621.

1265180861520 is a `hidden beast` number, since 1 + 2 + 6 + 5 + 1 + 8 + 0 + 8 + 615 + 20 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 655769561616 + 609411299904 = 809796^2 + 780648^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×1265180861520² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3842934 + ... + 4159146.

Almost surely, 2^{1265180861520} is an apocalyptic number.

1265180861520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1265180861520 is an abundant number, since it is smaller than the sum of its proper divisors (2984496240696).

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

1265180861520 is a wasteful number, since it uses less digits than its factorization.

1265180861520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321789 (or 321780 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 45.

The spelling of 1265180861520 in words is "one trillion, two hundred sixty-five billion, one hundred eighty million, eight hundred sixty-one thousand, five hundred twenty".