636990 has 32 divisors (see below), whose sum is σ = 1620000. Its totient is φ = 159744.

The previous prime is 636983. The next prime is 636997. The reversal of 636990 is 99636.

It is an interprime number because it is at equal distance from previous prime (636983) and next prime (636997).

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 636990.

It is not an unprimeable number, because it can be changed into a prime (636997) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 115 + ... + 1134.

It is an arithmetic number, because the mean of its divisors is an integer number (50625).

2⁶³⁶⁹⁹⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 636990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (810000).

636990 is an abundant number, since it is smaller than the sum of its proper divisors (983010).

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

636990 is a wasteful number, since it uses less digits than its factorization.

636990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1276.

The product of its (nonzero) digits is 8748, while the sum is 33.

The square root of 636990 is about 798.1165328447. The cubic root of 636990 is about 86.0420742385.

The spelling of 636990 in words is "six hundred thirty-six thousand, nine hundred ninety".