636880 has 40 divisors (see below), whose sum is σ = 1562400. Its totient is φ = 240768.

The previous prime is 636877. The next prime is 636917. The reversal of 636880 is 88636.

636880 = T₆₅ + T₆₆ + ... + T₁₅₉.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×636880² = 811232268800, which contains 22 as substring.

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1311 + ... + 1729.

It is an arithmetic number, because the mean of its divisors is an integer number (39060).

2⁶³⁶⁸⁸⁰ 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 636880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (781200).

636880 is an abundant number, since it is smaller than the sum of its proper divisors (925520).

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

636880 is a wasteful number, since it uses less digits than its factorization.

636880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451 (or 445 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 636880 is about 798.0476176269. The cubic root of 636880 is about 86.0371211659.

The spelling of 636880 in words is "six hundred thirty-six thousand, eight hundred eighty".