378831921 has 12 divisors (see below), whose sum is σ = 546953328. Its totient is φ = 233127024.

The previous prime is 378831917. The next prime is 378831949. The reversal of 378831921 is 129138873.

It is not a de Polignac number, because 378831921 - 2² = 378831917 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (378831991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 373095 + ... + 374108.

It is an arithmetic number, because the mean of its divisors is an integer number (45579444).

Almost surely, 2^378831921 is an apocalyptic number.

It is an amenable number.

378831921 is a deficient number, since it is larger than the sum of its proper divisors (168121407).

378831921 is a wasteful number, since it uses less digits than its factorization.

378831921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 747232 (or 747219 counting only the distinct ones).

The product of its digits is 72576, while the sum is 42.

The square root of 378831921 is about 19463.6050360667. The cubic root of 378831921 is about 723.5727265601.

The spelling of 378831921 in words is "three hundred seventy-eight million, eight hundred thirty-one thousand, nine hundred twenty-one".