1921811408 has 20 divisors (see below), whose sum is σ = 4062010848. Its totient is φ = 873550560.

The previous prime is 1921811401. The next prime is 1921811417. The reversal of 1921811408 is 8041181291.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1921811401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5459516 + ... + 5459867.

Almost surely, 2^1921811408 is an apocalyptic number.

It is an amenable number.

1921811408 is an abundant number, since it is smaller than the sum of its proper divisors (2140199440).

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

1921811408 is a wasteful number, since it uses less digits than its factorization.

1921811408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10919402 (or 10919396 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 35.

The square root of 1921811408 is about 43838.4694988317. The cubic root of 1921811408 is about 1243.2837452082.

Adding to 1921811408 its reverse (8041181291), we get a palindrome (9962992699).

The spelling of 1921811408 in words is "one billion, nine hundred twenty-one million, eight hundred eleven thousand, four hundred eight".