399447989 has 4 divisors (see below), whose sum is σ = 412333440. Its totient is φ = 386562540.

The previous prime is 399447959. The next prime is 399448033. The reversal of 399447989 is 989744993.

It is a happy number.

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: 989744993 = 23 ⋅43032391.

It is a cyclic number.

It is not a de Polignac number, because 399447989 - 2¹² = 399443893 is a prime.

It is a super-2 number, since 2×399447989² = 319117391832288242, which contains 22 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 (399447959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6442679 + ... + 6442740.

It is an arithmetic number, because the mean of its divisors is an integer number (103083360).

Almost surely, 2^399447989 is an apocalyptic number.

It is an amenable number.

399447989 is a deficient number, since it is larger than the sum of its proper divisors (12885451).

399447989 is a wasteful number, since it uses less digits than its factorization.

399447989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12885450.

The product of its digits is 17635968, while the sum is 62.

The square root of 399447989 is about 19986.1949605221. The cubic root of 399447989 is about 736.4672060421.

The spelling of 399447989 in words is "three hundred ninety-nine million, four hundred forty-seven thousand, nine hundred eighty-nine".