1801981981836 has 72 divisors (see below), whose sum is σ = 4828813333344. Its totient is φ = 564640611840.

The previous prime is 1801981981781. The next prime is 1801981981871. The reversal of 1801981981836 is 6381891891081.

1801981981836 is a `hidden beast` number, since 1 + 80 + 198 + 198 + 183 + 6 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1285155 + ... + 2292506.

It is an arithmetic number, because the mean of its divisors is an integer number (67066851852).

Almost surely, 2^{1801981981836} is an apocalyptic number.

It is an amenable number.

1801981981836 is an abundant number, since it is smaller than the sum of its proper divisors (3026831351508).

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

1801981981836 is a wasteful number, since it uses less digits than its factorization.

1801981981836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3578511 (or 3578506 counting only the distinct ones).

The product of its (nonzero) digits is 5971968, while the sum is 63.

The spelling of 1801981981836 in words is "one trillion, eight hundred one billion, nine hundred eighty-one million, nine hundred eighty-one thousand, eight hundred thirty-six".