20649953616 has 160 divisors (see below), whose sum is σ = 58333409280. Its totient is φ = 6270566400.

The previous prime is 20649953609. The next prime is 20649953617. The reversal of 20649953616 is 61635994602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20649953617) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4606096 + ... + 4610576.

It is an arithmetic number, because the mean of its divisors is an integer number (364583808).

Almost surely, 2^20649953616 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 20649953616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29166704640).

20649953616 is an abundant number, since it is smaller than the sum of its proper divisors (37683455664).

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

20649953616 is a wasteful number, since it uses less digits than its factorization.

20649953616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4705 (or 4699 counting only the distinct ones).

The product of its (nonzero) digits is 2099520, while the sum is 51.

The spelling of 20649953616 in words is "twenty billion, six hundred forty-nine million, nine hundred fifty-three thousand, six hundred sixteen".