20543681890 has 16 divisors (see below), whose sum is σ = 36982514808. Its totient is φ = 8216608896.

The previous prime is 20543681881. The next prime is 20543681897. The reversal of 20543681890 is 9818634502.

It can be written as a sum of positive squares in 4 ways, for example, as 18162144289 + 2381537601 = 134767^2 + 48801^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20543681890.

It is not an unprimeable number, because it can be changed into a prime (20543681897) 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 7 ways as a sum of consecutive naturals, for example, 3267 + ... + 202726.

Almost surely, 2^20543681890 is an apocalyptic number.

20543681890 is a deficient number, since it is larger than the sum of its proper divisors (16438832918).

20543681890 is a wasteful number, since it uses less digits than its factorization.

20543681890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215973.

The product of its (nonzero) digits is 414720, while the sum is 46.

The spelling of 20543681890 in words is "twenty billion, five hundred forty-three million, six hundred eighty-one thousand, eight hundred ninety".