390940987 has 2 divisors, whose sum is σ = 390940988. Its totient is φ = 390940986.

The previous prime is 390940939. The next prime is 390940997. The reversal of 390940987 is 789049093.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-390940987 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 390940987.

It is not a weakly prime, because it can be changed into another prime (390940997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195470493 + 195470494.

It is an arithmetic number, because the mean of its divisors is an integer number (195470494).

Almost surely, 2^390940987 is an apocalyptic number.

390940987 is a deficient number, since it is larger than the sum of its proper divisors (1).

390940987 is an equidigital number, since it uses as much as digits as its factorization.

390940987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 489888, while the sum is 49.

The square root of 390940987 is about 19772.2276691323. The cubic root of 390940987 is about 731.2014911012.

The spelling of 390940987 in words is "three hundred ninety million, nine hundred forty thousand, nine hundred eighty-seven".