11551280778 has 32 divisors (see below), whose sum is σ = 25694486400. Its totient is φ = 3846680928.

The previous prime is 11551280773. The next prime is 11551280801. The reversal of 11551280778 is 87708215511.

11551280778 is a `hidden beast` number, since 1 + 1 + 551 + 28 + 0 + 7 + 78 = 666.

It is a super-2 number, since 2×11551280778² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (11551280773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47758 + ... + 159321.

It is an arithmetic number, because the mean of its divisors is an integer number (802952700).

Almost surely, 2^11551280778 is an apocalyptic number.

11551280778 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

11551280778 is an abundant number, since it is smaller than the sum of its proper divisors (14143205622).

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

11551280778 is a wasteful number, since it uses less digits than its factorization.

11551280778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 208123 (or 208117 counting only the distinct ones).

The product of its (nonzero) digits is 156800, while the sum is 45.

The spelling of 11551280778 in words is "eleven billion, five hundred fifty-one million, two hundred eighty thousand, seven hundred seventy-eight".