1821491810388 has 24 divisors (see below), whose sum is σ = 4722386175360. Its totient is φ = 607163936760.

The previous prime is 1821491810387. The next prime is 1821491810483. The reversal of 1821491810388 is 8830181941281.

1821491810388 is a `hidden beast` number, since 1 + 82 + 1 + 4 + 9 + 181 + 0 + 388 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821491810381) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8432832348 + ... + 8432832563.

It is an arithmetic number, because the mean of its divisors is an integer number (196766090640).

Almost surely, 2^{1821491810388} is an apocalyptic number.

1821491810388 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1821491810388 is an abundant number, since it is smaller than the sum of its proper divisors (2900894364972).

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

1821491810388 is a wasteful number, since it uses less digits than its factorization.

1821491810388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16865664924 (or 16865664916 counting only the distinct ones).

The product of its (nonzero) digits is 884736, while the sum is 54.

The spelling of 1821491810388 in words is "one trillion, eight hundred twenty-one billion, four hundred ninety-one million, eight hundred ten thousand, three hundred eighty-eight".