20649204285640 has 384 divisors, whose sum is σ = 59696258688000. Its totient is φ = 6379608356352.

The previous prime is 20649204285629. The next prime is 20649204285641. The reversal of 20649204285640 is 4658240294602.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (20649204285641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 153249739 + ... + 153384421.

It is an arithmetic number, because the mean of its divisors is an integer number (155459007000).

Almost surely, 2^{20649204285640} is an apocalyptic number.

20649204285640 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 20649204285640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29848129344000).

20649204285640 is an abundant number, since it is smaller than the sum of its proper divisors (39047054402360).

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

20649204285640 is a wasteful number, since it uses less digits than its factorization.

20649204285640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134929 (or 134918 counting only the distinct ones).

The product of its (nonzero) digits is 6635520, while the sum is 52.

The spelling of 20649204285640 in words is "twenty trillion, six hundred forty-nine billion, two hundred four million, two hundred eighty-five thousand, six hundred forty".