20649355776 has 180 divisors, whose sum is σ = 69326064522. Its totient is φ = 5899751424.

The previous prime is 20649355759. The next prime is 20649355799. The reversal of 20649355776 is 67755394602.

20649355776 is a `hidden beast` number, since 2 + 0 + 64 + 9 + 3 + 5 + 577 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 18885355776 + 1764000000 = 137424^2 + 42000^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 180066 + ... + 271518.

Almost surely, 2^20649355776 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 20649355776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34663032261).

20649355776 is an abundant number, since it is smaller than the sum of its proper divisors (48676708746).

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

20649355776 is an equidigital number, since it uses as much as digits as its factorization.

20649355776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91491 (or 91465 counting only the distinct ones).

The product of its (nonzero) digits is 9525600, while the sum is 54.

The spelling of 20649355776 in words is "twenty billion, six hundred forty-nine million, three hundred fifty-five thousand, seven hundred seventy-six".