1815440155668 has 30 divisors (see below), whose sum is σ = 4745919173226. Its totient is φ = 605146718448.

The previous prime is 1815440155649. The next prime is 1815440155703. The reversal of 1815440155668 is 8665510445181.

It is a happy number.

1815440155668 is a `hidden beast` number, since 1 + 81 + 5 + 4 + 4 + 0 + 1 + 556 + 6 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1382157625104 + 433282530564 = 1175652^2 + 658242^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 2801604855 + ... + 2801605502.

Almost surely, 2^{1815440155668} is an apocalyptic number.

1815440155668 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1815440155668 is an abundant number, since it is smaller than the sum of its proper divisors (2930479017558).

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

1815440155668 is a wasteful number, since it uses less digits than its factorization.

1815440155668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5603210373 (or 5603210362 counting only the distinct ones).

The product of its (nonzero) digits is 4608000, while the sum is 54.

The spelling of 1815440155668 in words is "one trillion, eight hundred fifteen billion, four hundred forty million, one hundred fifty-five thousand, six hundred sixty-eight".