6398781 has 8 divisors (see below), whose sum is σ = 8555520. Its totient is φ = 4253952.

The previous prime is 6398767. The next prime is 6398789. The reversal of 6398781 is 1878936.

6398781 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-6398781 is a prime.

It is a super-2 number, since 2×6398781² = 81888796571922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6398789) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1636 + ... + 3933.

It is an arithmetic number, because the mean of its divisors is an integer number (1069440).

Almost surely, 2^6398781 is an apocalyptic number.

It is an amenable number.

6398781 is a deficient number, since it is larger than the sum of its proper divisors (2156739).

6398781 is a wasteful number, since it uses less digits than its factorization.

6398781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5955.

The product of its digits is 72576, while the sum is 42.

The square root of 6398781 is about 2529.5811906322. The cubic root of 6398781 is about 185.6517648944.

The spelling of 6398781 in words is "six million, three hundred ninety-eight thousand, seven hundred eighty-one".