7128864 has 96 divisors (see below), whose sum is σ = 21450240. Its totient is φ = 2301696.

The previous prime is 7128833. The next prime is 7128907. The reversal of 7128864 is 4688217.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 31857 + ... + 32079.

It is an arithmetic number, because the mean of its divisors is an integer number (223440).

Almost surely, 2^7128864 is an apocalyptic number.

7128864 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 7128864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10725120).

7128864 is an abundant number, since it is smaller than the sum of its proper divisors (14321376).

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

7128864 is a wasteful number, since it uses less digits than its factorization.

7128864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279 (or 265 counting only the distinct ones).

The product of its digits is 21504, while the sum is 36.

The square root of 7128864 is about 2669.9932584185. The cubic root of 7128864 is about 192.4598353264.

Adding to 7128864 its sum of digits (36), we get a square (7128900 = 2670²).

The spelling of 7128864 in words is "seven million, one hundred twenty-eight thousand, eight hundred sixty-four".