394995989 has 4 divisors (see below), whose sum is σ = 395384640. Its totient is φ = 394607340.

The previous prime is 394995977. The next prime is 394996001. The reversal of 394995989 is 989599493.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 989599493 = 41 ⋅24136573.

It is an interprime number because it is at equal distance from previous prime (394995977) and next prime (394996001).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-394995989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (394995089) 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, 192797 + ... + 194834.

It is an arithmetic number, because the mean of its divisors is an integer number (98846160).

Almost surely, 2^394995989 is an apocalyptic number.

It is an amenable number.

394995989 is a deficient number, since it is larger than the sum of its proper divisors (388651).

394995989 is a wasteful number, since it uses less digits than its factorization.

394995989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388650.

The product of its digits is 28343520, while the sum is 65.

The square root of 394995989 is about 19874.5060064395. The cubic root of 394995989 is about 733.7209086015.

The spelling of 394995989 in words is "three hundred ninety-four million, nine hundred ninety-five thousand, nine hundred eighty-nine".