1811113665840 has 80 divisors (see below), whose sum is σ = 6238280412000. Its totient is φ = 482963643648.

The previous prime is 1811113665811. The next prime is 1811113665857. The reversal of 1811113665840 is 485663111181.

1811113665840 is a `hidden beast` number, since 1 + 8 + 1 + 1 + 1 + 1 + 3 + 66 + 584 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (80).

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

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 419237115 + ... + 419241434.

It is an arithmetic number, because the mean of its divisors is an integer number (77978505150).

Almost surely, 2^{1811113665840} is an apocalyptic number.

1811113665840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1811113665840 is an abundant number, since it is smaller than the sum of its proper divisors (4427166746160).

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

1811113665840 is a wasteful number, since it uses less digits than its factorization.

1811113665840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 838478571 (or 838478559 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 45.

The spelling of 1811113665840 in words is "one trillion, eight hundred eleven billion, one hundred thirteen million, six hundred sixty-five thousand, eight hundred forty".