636649420 has 24 divisors (see below), whose sum is σ = 1458506448. Its totient is φ = 231508800.

The previous prime is 636649399. The next prime is 636649423. The reversal of 636649420 is 24946636.

It is not an unprimeable number, because it can be changed into a prime (636649423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1446711 + ... + 1447150.

It is an arithmetic number, because the mean of its divisors is an integer number (60771102).

Almost surely, 2^636649420 is an apocalyptic number.

It is an amenable number.

636649420 is an abundant number, since it is smaller than the sum of its proper divisors (821857028).

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

636649420 is a wasteful number, since it uses less digits than its factorization.

636649420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2893881 (or 2893879 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 40.

The square root of 636649420 is about 25231.9127297159. The cubic root of 636649420 is about 860.2673677430.

It can be divided in two parts, 636 and 649420, that added together give a palindrome (650056).

The spelling of 636649420 in words is "six hundred thirty-six million, six hundred forty-nine thousand, four hundred twenty".