636549040 has 80 divisors (see below), whose sum is σ = 1535901696. Its totient is φ = 245088000.

The previous prime is 636549013. The next prime is 636549041. The reversal of 636549040 is 40945636.

It is a happy number.

636549040 is a nontrivial binomial coefficient, being equal to C(35681, 2).

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

It is not an unprimeable number, because it can be changed into a prime (636549041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 552465 + ... + 553615.

Almost surely, 2^636549040 is an apocalyptic number.

636549040 is the 35680-th triangular number.

636549040 is the 11894-th centered nonagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 636549040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (767950848).

636549040 is an abundant number, since it is smaller than the sum of its proper divisors (899352656).

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

636549040 is a wasteful number, since it uses less digits than its factorization.

636549040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1418 (or 1412 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 37.

The square root of 636549040 is about 25229.9235036494. The cubic root of 636549040 is about 860.2221528129. Note that the first 3 decimals are identical.

It can be divided in two parts, 636 and 549040, that added together give a triangular number (549676 = T₁₀₄₈).

The spelling of 636549040 in words is "six hundred thirty-six million, five hundred forty-nine thousand, forty".