6440281 has 8 divisors (see below), whose sum is σ = 6715904. Its totient is φ = 6168960.

The previous prime is 6440249. The next prime is 6440303. The reversal of 6440281 is 1820446.

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

It is a 4-Lehmer number, since φ(6440281) divides (6440281-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 6440281 - 2⁵ = 6440249 is a prime.

It is a super-2 number, since 2×6440281² = 82954438717922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6440201) 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, 2185 + ... + 4201.

It is an arithmetic number, because the mean of its divisors is an integer number (839488).

Almost surely, 2^6440281 is an apocalyptic number.

It is an amenable number.

6440281 is a deficient number, since it is larger than the sum of its proper divisors (275623).

6440281 is a wasteful number, since it uses less digits than its factorization.

6440281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2151.

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 6440281 is about 2537.7708722420. The cubic root of 6440281 is about 186.0522553298.

The spelling of 6440281 in words is "six million, four hundred forty thousand, two hundred eighty-one".