1921138944 has 216 divisors, whose sum is σ = 5601949920. Its totient is φ = 582819840.

The previous prime is 1921138903. The next prime is 1921138949. The reversal of 1921138944 is 4498311291.

Its product of digits (62208) is a multiple of the sum of its prime divisors (192).

It is a junction number, because it is equal to n+sod(n) for n = 1921138896 and 1921138905.

It is not an unprimeable number, because it can be changed into a prime (1921138949) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14022844 + ... + 14022980.

Almost surely, 2^1921138944 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1921138944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2800974960).

1921138944 is an abundant number, since it is smaller than the sum of its proper divisors (3680810976).

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

1921138944 is a wasteful number, since it uses less digits than its factorization.

1921138944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237 (or 192 counting only the distinct ones).

The product of its digits is 62208, while the sum is 42.

The square root of 1921138944 is about 43830.7990344689. The cubic root of 1921138944 is about 1243.1387151787.

The spelling of 1921138944 in words is "one billion, nine hundred twenty-one million, one hundred thirty-eight thousand, nine hundred forty-four".