636621642 has 48 divisors (see below), whose sum is σ = 1443985920. Its totient is φ = 202456800.

The previous prime is 636621613. The next prime is 636621653. The reversal of 636621642 is 246126636.

636621642 is a `hidden beast` number, since 6 + 3 + 6 + 6 + 2 + 1 + 642 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 636621597 and 636621606.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 31584 + ... + 47652.

It is an arithmetic number, because the mean of its divisors is an integer number (30083040).

Almost surely, 2^636621642 is an apocalyptic number.

636621642 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 636621642, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (721992960).

636621642 is an abundant number, since it is smaller than the sum of its proper divisors (807364278).

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

636621642 is a wasteful number, since it uses less digits than its factorization.

636621642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16179 (or 16176 counting only the distinct ones).

The product of its digits is 62208, while the sum is 36.

The square root of 636621642 is about 25231.3622700004. The cubic root of 636621642 is about 860.2548559620.

The spelling of 636621642 in words is "six hundred thirty-six million, six hundred twenty-one thousand, six hundred forty-two".