6651720 has 80 divisors (see below), whose sum is σ = 22368060. Its totient is φ = 1772928.

The previous prime is 6651707. The next prime is 6651727. The reversal of 6651720 is 271566.

6651720 is a `hidden beast` number, since 6 + 651 + 7 + 2 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 6625476 + 26244 = 2574^2 + 162^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (6651727) 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 in 19 ways as a sum of consecutive naturals, for example, 2214 + ... + 4266.

Almost surely, 2^6651720 is an apocalyptic number.

6651720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6651720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11184030).

6651720 is an abundant number, since it is smaller than the sum of its proper divisors (15716340).

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

6651720 is a wasteful number, since it uses less digits than its factorization.

6651720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2076 (or 2063 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 6651720 is about 2579.0928637798. The cubic root of 6651720 is about 188.0664470116.

The spelling of 6651720 in words is "six million, six hundred fifty-one thousand, seven hundred twenty".