7720664 has 16 divisors (see below), whose sum is σ = 16544400. Its totient is φ = 3308832.

The previous prime is 7720649. The next prime is 7720667. The reversal of 7720664 is 4660277.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 7720664.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7720667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68879 + ... + 68990.

It is an arithmetic number, because the mean of its divisors is an integer number (1034025).

Almost surely, 2^7720664 is an apocalyptic number.

It is an amenable number.

7720664 is an abundant number, since it is smaller than the sum of its proper divisors (8823736).

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

7720664 is a wasteful number, since it uses less digits than its factorization.

7720664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137882 (or 137878 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 32.

The square root of 7720664 is about 2778.6082847354. The cubic root of 7720664 is about 197.6445686155.

The spelling of 7720664 in words is "seven million, seven hundred twenty thousand, six hundred sixty-four".