20511409838 has 4 divisors (see below), whose sum is σ = 30767114760. Its totient is φ = 10255704918.

The previous prime is 20511409819. The next prime is 20511409843. The reversal of 20511409838 is 83890411502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83890411502 = 2 ⋅41945205751.

It is a junction number, because it is equal to n+sod(n) for n = 20511409795 and 20511409804.

It is a congruent number.

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 as a sum of consecutive naturals, namely, 5127852458 + ... + 5127852461.

It is an arithmetic number, because the mean of its divisors is an integer number (7691778690).

Almost surely, 2^20511409838 is an apocalyptic number.

20511409838 is a deficient number, since it is larger than the sum of its proper divisors (10255704922).

20511409838 is a wasteful number, since it uses less digits than its factorization.

20511409838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10255704921.

The product of its (nonzero) digits is 69120, while the sum is 41.

The spelling of 20511409838 in words is "twenty billion, five hundred eleven million, four hundred nine thousand, eight hundred thirty-eight".