20653136640 has 432 divisors, whose sum is σ = 74327198400. Its totient is φ = 5290721280.

The previous prime is 20653136521. The next prime is 20653136641. The reversal of 20653136640 is 4663135602.

20653136640 is a `hidden beast` number, since 2 + 0 + 6 + 5 + 3 + 1 + 3 + 6 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 20653136595 and 20653136604.

It is not an unprimeable number, because it can be changed into a prime (20653136641) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 34479061 + ... + 34479659.

It is an arithmetic number, because the mean of its divisors is an integer number (172053700).

Almost surely, 2^20653136640 is an apocalyptic number.

20653136640 is a gapful number since it is divisible by the number (20) 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 20653136640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37163599200).

20653136640 is an abundant number, since it is smaller than the sum of its proper divisors (53674061760).

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

20653136640 is a wasteful number, since it uses less digits than its factorization.

20653136640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 740 (or 723 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 36.

The spelling of 20653136640 in words is "twenty billion, six hundred fifty-three million, one hundred thirty-six thousand, six hundred forty".