21061636146 has 64 divisors (see below), whose sum is σ = 47956930560. Its totient is φ = 6848537040.

The previous prime is 21061636129. The next prime is 21061636157. The reversal of 21061636146 is 64163616012.

It is a happy number.

21061636146 is a `hidden beast` number, since 2 + 1 + 0 + 6 + 1 + 636 + 14 + 6 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 21061636146.

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 31 ways as a sum of consecutive naturals, for example, 765651 + ... + 792681.

It is an arithmetic number, because the mean of its divisors is an integer number (749327040).

Almost surely, 2^21061636146 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21061636146, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23978465280).

21061636146 is an abundant number, since it is smaller than the sum of its proper divisors (26895294414).

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

21061636146 is a wasteful number, since it uses less digits than its factorization.

21061636146 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27396 (or 27390 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The spelling of 21061636146 in words is "twenty-one billion, sixty-one million, six hundred thirty-six thousand, one hundred forty-six".