651664 has 30 divisors (see below), whose sum is σ = 1372866. Its totient is φ = 299520.

The previous prime is 651649. The next prime is 651667. The reversal of 651664 is 466156.

It can be written as a sum of positive squares in 3 ways, for example, as 11664 + 640000 = 108^2 + 800^2 .

It is not an unprimeable number, because it can be changed into a prime (651667) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2584 + ... + 2824.

2⁶⁵¹⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 651664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (686433).

651664 is an abundant number, since it is smaller than the sum of its proper divisors (721202).

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

651664 is a wasteful number, since it uses less digits than its factorization.

651664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 275 (or 256 counting only the distinct ones).

The product of its digits is 4320, while the sum is 28.

The square root of 651664 is about 807.2570842055. The cubic root of 651664 is about 86.6977666164.

The spelling of 651664 in words is "six hundred fifty-one thousand, six hundred sixty-four".