6449781 has 8 divisors (see below), whose sum is σ = 9261280. Its totient is φ = 3969072.

The previous prime is 6449777. The next prime is 6449791. The reversal of 6449781 is 1879446.

It is a happy number.

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

It is not a de Polignac number, because 6449781 - 2² = 6449777 is a prime.

It is a super-2 number, since 2×6449781² = 83199349895922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 165379 = 6449781 / (6 + 4 + 4 + 9 + 7 + 8 + 1).

It is a Duffinian number.

6449781 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6449731) 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, 82651 + ... + 82728.

It is an arithmetic number, because the mean of its divisors is an integer number (1157660).

Almost surely, 2^6449781 is an apocalyptic number.

It is an amenable number.

6449781 is a deficient number, since it is larger than the sum of its proper divisors (2811499).

6449781 is a wasteful number, since it uses less digits than its factorization.

6449781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165395.

The product of its digits is 48384, while the sum is 39.

The square root of 6449781 is about 2539.6419038912. The cubic root of 6449781 is about 186.1436917161.

The spelling of 6449781 in words is "six million, four hundred forty-nine thousand, seven hundred eighty-one".