1921643338 has 8 divisors (see below), whose sum is σ = 2883687840. Its totient is φ = 960414060.

The previous prime is 1921643333. The next prime is 1921643357. The reversal of 1921643338 is 8333461291.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1921643338.

It is not an unprimeable number, because it can be changed into a prime (1921643333) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 197878 + ... + 207361.

It is an arithmetic number, because the mean of its divisors is an integer number (360460980).

Almost surely, 2^1921643338 is an apocalyptic number.

1921643338 is a deficient number, since it is larger than the sum of its proper divisors (962044502).

1921643338 is a wasteful number, since it uses less digits than its factorization.

1921643338 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407612.

The product of its digits is 93312, while the sum is 40.

The square root of 1921643338 is about 43836.5525332456. The cubic root of 1921643338 is about 1243.2475007931.

The spelling of 1921643338 in words is "one billion, nine hundred twenty-one million, six hundred forty-three thousand, three hundred thirty-eight".