1921204631808 has 432 divisors, whose sum is σ = 7209729414720. Its totient is φ = 499013222400.

The previous prime is 1921204631783. The next prime is 1921204631809. The reversal of 1921204631808 is 8081364021291.

1921204631808 is a `hidden beast` number, since 1 + 9 + 2 + 1 + 2 + 0 + 4 + 631 + 8 + 0 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (432).

It is not an unprimeable number, because it can be changed into a prime (1921204631809) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3467728 + ... + 3983408.

It is an arithmetic number, because the mean of its divisors is an integer number (16689188460).

Almost surely, 2^{1921204631808} is an apocalyptic number.

1921204631808 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1921204631808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3604864707360).

1921204631808 is an abundant number, since it is smaller than the sum of its proper divisors (5288524782912).

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

1921204631808 is a wasteful number, since it uses less digits than its factorization.

1921204631808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515731 (or 515704 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 45.

The spelling of 1921204631808 in words is "one trillion, nine hundred twenty-one billion, two hundred four million, six hundred thirty-one thousand, eight hundred eight".