636720 has 80 divisors (see below), whose sum is σ = 2261760. Its totient is φ = 145152.

The previous prime is 636719. The next prime is 636721. The reversal of 636720 is 27636.

636720 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (636719) and next prime (636721).

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

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (636721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1491 + ... + 1869.

It is an arithmetic number, because the mean of its divisors is an integer number (28272).

2⁶³⁶⁷²⁰ is an apocalyptic number.

636720 is a gapful number since it is divisible by the number (60) 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 636720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1130880).

636720 is an abundant number, since it is smaller than the sum of its proper divisors (1625040).

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

636720 is a wasteful number, since it uses less digits than its factorization.

636720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 402 (or 396 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 24.

The square root of 636720 is about 797.9473666853. The cubic root of 636720 is about 86.0299156786.

The spelling of 636720 in words is "six hundred thirty-six thousand, seven hundred twenty".