20551021636 has 24 divisors (see below), whose sum is σ = 36447896576. Its totient is φ = 10138232160.

The previous prime is 20551021607. The next prime is 20551021657. The reversal of 20551021636 is 63612015502.

It is a junction number, because it is equal to n+sod(n) for n = 20551021598 and 20551021607.

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 7 ways as a sum of consecutive naturals, for example, 19806 + ... + 203701.

Almost surely, 2^20551021636 is an apocalyptic number.

It is an amenable number.

20551021636 is a deficient number, since it is larger than the sum of its proper divisors (15896874940).

20551021636 is a wasteful number, since it uses less digits than its factorization.

20551021636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223819 (or 223817 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 31.

The spelling of 20551021636 in words is "twenty billion, five hundred fifty-one million, twenty-one thousand, six hundred thirty-six".