6401987 has 2 divisors, whose sum is σ = 6401988. Its totient is φ = 6401986.

The previous prime is 6401977. The next prime is 6402001. The reversal of 6401987 is 7891046.

6401987 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6401987 - 2⁴ = 6401971 is a prime.

It is not a weakly prime, because it can be changed into another prime (6401977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3200993 + 3200994.

It is an arithmetic number, because the mean of its divisors is an integer number (3200994).

Almost surely, 2^6401987 is an apocalyptic number.

6401987 is a deficient number, since it is larger than the sum of its proper divisors (1).

6401987 is an equidigital number, since it uses as much as digits as its factorization.

6401987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 6401987 is about 2530.2148130149. The cubic root of 6401987 is about 185.6827656002.

The spelling of 6401987 in words is "six million, four hundred one thousand, nine hundred eighty-seven".