20998636 has 6 divisors (see below), whose sum is σ = 36747620. Its totient is φ = 10499316.

The previous prime is 20998633. The next prime is 20998673. The reversal of 20998636 is 63689902.

It is a junction number, because it is equal to n+sod(n) for n = 20998592 and 20998601.

It is not an unprimeable number, because it can be changed into a prime (20998633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2624826 + ... + 2624833.

Almost surely, 2^20998636 is an apocalyptic number.

It is an amenable number.

20998636 is a deficient number, since it is larger than the sum of its proper divisors (15748984).

20998636 is a wasteful number, since it uses less digits than its factorization.

20998636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5249663 (or 5249661 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 43.

The square root of 20998636 is about 4582.4268679380. The cubic root of 20998636 is about 275.8864442190.

The spelling of 20998636 in words is "twenty million, nine hundred ninety-eight thousand, six hundred thirty-six".