381694321 has 4 divisors (see below), whose sum is σ = 385629412. Its totient is φ = 377759232.

The previous prime is 381694301. The next prime is 381694337. The reversal of 381694321 is 123496183.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 123496183 = 1033 ⋅119551.

It can be written as a sum of positive squares in 2 ways, for example, as 311134321 + 70560000 = 17639^2 + 8400^2 .

It is a cyclic number.

It is not a de Polignac number, because 381694321 - 2¹⁹ = 381170033 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (381694301) 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, 1967400 + ... + 1967593.

It is an arithmetic number, because the mean of its divisors is an integer number (96407353).

Almost surely, 2^381694321 is an apocalyptic number.

It is an amenable number.

381694321 is a deficient number, since it is larger than the sum of its proper divisors (3935091).

381694321 is an equidigital number, since it uses as much as digits as its factorization.

381694321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3935090.

The product of its digits is 31104, while the sum is 37.

The square root of 381694321 is about 19536.9987715616. The cubic root of 381694321 is about 725.3905599190.

The spelling of 381694321 in words is "three hundred eighty-one million, six hundred ninety-four thousand, three hundred twenty-one".