390669991 has 4 divisors (see below), whose sum is σ = 404141400. Its totient is φ = 377198584.

The previous prime is 390669989. The next prime is 390670003. The reversal of 390669991 is 199966093.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 390669991 - 2¹ = 390669989 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 (390669901) 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, 6735661 + ... + 6735718.

It is an arithmetic number, because the mean of its divisors is an integer number (101035350).

Almost surely, 2^390669991 is an apocalyptic number.

390669991 is a deficient number, since it is larger than the sum of its proper divisors (13471409).

390669991 is a wasteful number, since it uses less digits than its factorization.

390669991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13471408.

The product of its (nonzero) digits is 708588, while the sum is 52.

The square root of 390669991 is about 19765.3735355545. The cubic root of 390669991 is about 731.0324984320.

The spelling of 390669991 in words is "three hundred ninety million, six hundred sixty-nine thousand, nine hundred ninety-one".