20644690961016 has 192 divisors, whose sum is σ = 59557221734400. Its totient is φ = 6448874745600.

The previous prime is 20644690961009. The next prime is 20644690961087. The reversal of 20644690961016 is 61016909644602.

20644690961016 is a `hidden beast` number, since 2 + 0 + 6 + 4 + 4 + 6 + 9 + 0 + 9 + 610 + 16 = 666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 16832845 + ... + 18017603.

It is an arithmetic number, because the mean of its divisors is an integer number (310193863200).

Almost surely, 2^{20644690961016} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20644690961016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29778610867200).

20644690961016 is an abundant number, since it is smaller than the sum of its proper divisors (38912530773384).

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

20644690961016 is a wasteful number, since it uses less digits than its factorization.

20644690961016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1185050 (or 1185043 counting only the distinct ones).

The product of its (nonzero) digits is 3359232, while the sum is 54.

The spelling of 20644690961016 in words is "twenty trillion, six hundred forty-four billion, six hundred ninety million, nine hundred sixty-one thousand, sixteen".