6451668 has 18 divisors (see below), whose sum is σ = 16308474. Its totient is φ = 2150544.

The previous prime is 6451657. The next prime is 6451691. The reversal of 6451668 is 8661546.

6451668 is a `hidden beast` number, since 645 + 1 + 6 + 6 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 6290064 + 161604 = 2508^2 + 402^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 179213 = 6451668 / (6 + 4 + 5 + 1 + 6 + 6 + 8).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 89571 + ... + 89642.

Almost surely, 2^6451668 is an apocalyptic number.

It is an amenable number.

6451668 is an abundant number, since it is smaller than the sum of its proper divisors (9856806).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6451668 is a wasteful number, since it uses less digits than its factorization.

6451668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179223 (or 179218 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 6451668 is about 2540.0133857915. The cubic root of 6451668 is about 186.1618431798.

The spelling of 6451668 in words is "six million, four hundred fifty-one thousand, six hundred sixty-eight".