20801638436 has 6 divisors (see below), whose sum is σ = 36402867270. Its totient is φ = 10400819216.

The previous prime is 20801638427. The next prime is 20801638439. The reversal of 20801638436 is 63483610802.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 18034878436 + 2766760000 = 134294^2 + 52600^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20801638393 and 20801638402.

It is not an unprimeable number, because it can be changed into a prime (20801638439) 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 as a sum of consecutive naturals, namely, 2600204801 + ... + 2600204808.

It is an arithmetic number, because the mean of its divisors is an integer number (6067144545).

Almost surely, 2^20801638436 is an apocalyptic number.

It is an amenable number.

20801638436 is a deficient number, since it is larger than the sum of its proper divisors (15601228834).

20801638436 is a wasteful number, since it uses less digits than its factorization.

20801638436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5200409613 (or 5200409611 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 41.

The spelling of 20801638436 in words is "twenty billion, eight hundred one million, six hundred thirty-eight thousand, four hundred thirty-six".