6664440720 has 80 divisors (see below), whose sum is σ = 23611167360. Its totient is φ = 1523300352.

The previous prime is 6664440701. The next prime is 6664440737. The reversal of 6664440720 is 270444666.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×6664440720² = 88829540220788236800, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1981785 + ... + 1985144.

It is an arithmetic number, because the mean of its divisors is an integer number (295139592).

Almost surely, 2^6664440720 is an apocalyptic number.

6664440720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

6664440720 is an abundant number, since it is smaller than the sum of its proper divisors (16946726640).

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

6664440720 is a wasteful number, since it uses less digits than its factorization.

6664440720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3966952 (or 3966946 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 39.

The square root of 6664440720 is about 81636.0258709352. The cubic root of 6664440720 is about 1881.8625648432.

The spelling of 6664440720 in words is "six billion, six hundred sixty-four million, four hundred forty thousand, seven hundred twenty".