394659821 has 8 divisors (see below), whose sum is σ = 397599384. Its totient is φ = 391728960.

The previous prime is 394659817. The next prime is 394659833. The reversal of 394659821 is 128956493.

It can be written as a sum of positive squares in 4 ways, for example, as 99301225 + 295358596 = 9965^2 + 17186^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 394659821 - 2² = 394659817 is a prime.

It is a super-3 number, since 3×394659821³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (394659841) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 109175 + ... + 112731.

It is an arithmetic number, because the mean of its divisors is an integer number (49699923).

Almost surely, 2^394659821 is an apocalyptic number.

It is an amenable number.

394659821 is a deficient number, since it is larger than the sum of its proper divisors (2939563).

394659821 is a wasteful number, since it uses less digits than its factorization.

394659821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4351.

The product of its digits is 466560, while the sum is 47.

The square root of 394659821 is about 19866.0469394392. The cubic root of 394659821 is about 733.5127010051.

The spelling of 394659821 in words is "three hundred ninety-four million, six hundred fifty-nine thousand, eight hundred twenty-one".