20781916550 has 96 divisors (see below), whose sum is σ = 39955032000. Its totient is φ = 8039360000.

The previous prime is 20781916541. The next prime is 20781916567. The reversal of 20781916550 is 5561918702.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 53423756 + ... + 53424144.

It is an arithmetic number, because the mean of its divisors is an integer number (416198250).

Almost surely, 2^20781916550 is an apocalyptic number.

20781916550 is a deficient number, since it is larger than the sum of its proper divisors (19173115450).

20781916550 is a wasteful number, since it uses less digits than its factorization.

20781916550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 722 (or 717 counting only the distinct ones).

The product of its (nonzero) digits is 151200, while the sum is 44.

The spelling of 20781916550 in words is "twenty billion, seven hundred eighty-one million, nine hundred sixteen thousand, five hundred fifty".