636287440 has 20 divisors (see below), whose sum is σ = 1479368484. Its totient is φ = 254514944.

The previous prime is 636287437. The next prime is 636287453. The reversal of 636287440 is 44782636.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 289136016 + 347151424 = 17004^2 + 18632^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 636287393 and 636287402.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 3976717 + ... + 3976876.

Almost surely, 2^636287440 is an apocalyptic number.

It is an amenable number.

636287440 is an abundant number, since it is smaller than the sum of its proper divisors (843081044).

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

636287440 is a wasteful number, since it uses less digits than its factorization.

636287440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7953606 (or 7953600 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 40.

The square root of 636287440 is about 25224.7386507769. The cubic root of 636287440 is about 860.1042959864.

The spelling of 636287440 in words is "six hundred thirty-six million, two hundred eighty-seven thousand, four hundred forty".