390487991 has 2 divisors, whose sum is σ = 390487992. Its totient is φ = 390487990.

The previous prime is 390487967. The next prime is 390488029. The reversal of 390487991 is 199784093.

It is a weak prime.

It is an emirp because it is prime and its reverse (199784093) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 390487991 - 2⁶ = 390487927 is a prime.

It is a super-2 number, since 2×390487991² = 304961742230432162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (390487921) 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 as a sum of consecutive naturals, namely, 195243995 + 195243996.

It is an arithmetic number, because the mean of its divisors is an integer number (195243996).

Almost surely, 2^390487991 is an apocalyptic number.

390487991 is a deficient number, since it is larger than the sum of its proper divisors (1).

390487991 is an equidigital number, since it uses as much as digits as its factorization.

390487991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 489888, while the sum is 50.

The square root of 390487991 is about 19760.7689880733. The cubic root of 390487991 is about 730.9189596533.

The spelling of 390487991 in words is "three hundred ninety million, four hundred eighty-seven thousand, nine hundred ninety-one".