20998038650 has 12 divisors (see below), whose sum is σ = 39056351982. Its totient is φ = 8399215440.

The previous prime is 20998038643. The next prime is 20998038653. The reversal of 20998038650 is 5683089902.

It is a Cunningham number, because it is equal to 144907²+1.

It can be written as a sum of positive squares in 3 ways, for example, as 19351870321 + 1646168329 = 139111^2 + 40573^2 .

It is a Harshad number since it is a multiple of its sum of digits (50), and also a Moran number because the ratio is a prime number: 419960773 = 20998038650 / (2 + 0 + 9 + 9 + 8 + 0 + 3 + 8 + 6 + 5 + 0).

It is not an unprimeable number, because it can be changed into a prime (20998038653) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 209980337 + ... + 209980436.

Almost surely, 2^20998038650 is an apocalyptic number.

20998038650 is a deficient number, since it is larger than the sum of its proper divisors (18058313332).

20998038650 is a wasteful number, since it uses less digits than its factorization.

20998038650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419960785 (or 419960780 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 50.

The spelling of 20998038650 in words is "twenty billion, nine hundred ninety-eight million, thirty-eight thousand, six hundred fifty".