20647037664 has 144 divisors (see below), whose sum is σ = 66261751920. Its totient is φ = 6040903680.

The previous prime is 20647037639. The next prime is 20647037711. The reversal of 20647037664 is 46673074602.

20647037664 is a `hidden beast` number, since 206 + 4 + 70 + 376 + 6 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a congruent number.

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, 20497 + ... + 204240.

It is an arithmetic number, because the mean of its divisors is an integer number (460151055).

Almost surely, 2^20647037664 is an apocalyptic number.

20647037664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20647037664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33130875960).

20647037664 is an abundant number, since it is smaller than the sum of its proper divisors (45614714256).

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

20647037664 is a wasteful number, since it uses less digits than its factorization.

20647037664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224793 (or 224782 counting only the distinct ones).

The product of its (nonzero) digits is 1016064, while the sum is 45.

The spelling of 20647037664 in words is "twenty billion, six hundred forty-seven million, thirty-seven thousand, six hundred sixty-four".