7217664 has 80 divisors (see below), whose sum is σ = 19903488. Its totient is φ = 2322432.

The previous prime is 7217659. The next prime is 7217671. The reversal of 7217664 is 4667127.

7217664 is nontrivially palindromic in base 15.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56769 + ... + 56895.

Almost surely, 2^7217664 is an apocalyptic number.

7217664 is a gapful number since it is divisible by the number (74) 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 7217664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9951744).

7217664 is an abundant number, since it is smaller than the sum of its proper divisors (12685824).

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

7217664 is a wasteful number, since it uses less digits than its factorization.

7217664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185 (or 169 counting only the distinct ones).

The product of its digits is 14112, while the sum is 33.

The square root of 7217664 is about 2686.5710487534. The cubic root of 7217664 is about 193.2556591133.

It can be divided in two parts, 721 and 7664, that added together give a triangular number (8385 = T₁₂₉).

The spelling of 7217664 in words is "seven million, two hundred seventeen thousand, six hundred sixty-four".