20805874881 has 32 divisors (see below), whose sum is σ = 32647909248. Its totient is φ = 11643939840.

The previous prime is 20805874877. The next prime is 20805874913. The reversal of 20805874881 is 18847850802.

It is not a de Polignac number, because 20805874881 - 2² = 20805874877 is a prime.

It is a super-2 number, since 2×20805874881² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20805874381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 320146 + ... + 379611.

It is an arithmetic number, because the mean of its divisors is an integer number (1020247164).

Almost surely, 2^20805874881 is an apocalyptic number.

It is an amenable number.

20805874881 is a deficient number, since it is larger than the sum of its proper divisors (11842034367).

20805874881 is a wasteful number, since it uses less digits than its factorization.

20805874881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 699841.

The product of its (nonzero) digits is 1146880, while the sum is 51.

The spelling of 20805874881 in words is "twenty billion, eight hundred five million, eight hundred seventy-four thousand, eight hundred eighty-one".