20818942881 has 16 divisors (see below), whose sum is σ = 30292669440. Its totient is φ = 12613136720.

The previous prime is 20818942873. The next prime is 20818942931. The reversal of 20818942881 is 18824981802.

It is a cyclic number.

It is not a de Polignac number, because 20818942881 - 2³ = 20818942873 is a prime.

It is a super-2 number, since 2×20818942881² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20818942981) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12861 + ... + 204458.

It is an arithmetic number, because the mean of its divisors is an integer number (1893291840).

Almost surely, 2^20818942881 is an apocalyptic number.

It is an amenable number.

20818942881 is a deficient number, since it is larger than the sum of its proper divisors (9473726559).

20818942881 is a wasteful number, since it uses less digits than its factorization.

20818942881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220236.

The product of its (nonzero) digits is 589824, while the sum is 51.

The spelling of 20818942881 in words is "twenty billion, eight hundred eighteen million, nine hundred forty-two thousand, eight hundred eighty-one".