636123642 has 128 divisors (see below), whose sum is σ = 1664409600. Its totient is φ = 157248000.

The previous prime is 636123641. The next prime is 636123643. The reversal of 636123642 is 246321636.

It is an interprime number because it is at equal distance from previous prime (636123641) and next prime (636123643).

It is a super-2 number, since 2×636123642² = 809306575822688328, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (636123641) 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 63 ways as a sum of consecutive naturals, for example, 1058142 + ... + 1058742.

It is an arithmetic number, because the mean of its divisors is an integer number (13003200).

Almost surely, 2^636123642 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 636123642, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (832204800).

636123642 is an abundant number, since it is smaller than the sum of its proper divisors (1028285958).

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

636123642 is a wasteful number, since it uses less digits than its factorization.

636123642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 732.

The product of its digits is 31104, while the sum is 33.

The square root of 636123642 is about 25221.4916688129. The cubic root of 636123642 is about 860.0304847676.

It can be divided in two parts, 6361 and 23642, that added together give a palindrome (30003).

The spelling of 636123642 in words is "six hundred thirty-six million, one hundred twenty-three thousand, six hundred forty-two".