20649988672 has 168 divisors, whose sum is σ = 44915328000. Its totient is φ = 9414107136.

The previous prime is 20649988663. The next prime is 20649988687. The reversal of 20649988672 is 27688994602.

It is a self number, because there is not a number n which added to its sum of digits gives 20649988672.

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, 138590454 + ... + 138590602.

Almost surely, 2^20649988672 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 20649988672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22457664000).

20649988672 is an abundant number, since it is smaller than the sum of its proper divisors (24265339328).

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

20649988672 is a wasteful number, since it uses less digits than its factorization.

20649988672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 381 (or 354 counting only the distinct ones).

The product of its (nonzero) digits is 20901888, while the sum is 61.

The spelling of 20649988672 in words is "twenty billion, six hundred forty-nine million, nine hundred eighty-eight thousand, six hundred seventy-two".