20218346881 has 4 divisors (see below), whose sum is σ = 20227379200. Its totient is φ = 20209314564.

The previous prime is 20218346873. The next prime is 20218346923. The reversal of 20218346881 is 18864381202.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18864381202 = 2 ⋅9432190601.

It is a cyclic number.

It is not a de Polignac number, because 20218346881 - 2³ = 20218346873 is a prime.

It is a super-2 number, since 2×20218346881² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20218346831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4512801 + ... + 4517278.

It is an arithmetic number, because the mean of its divisors is an integer number (5056844800).

Almost surely, 2^20218346881 is an apocalyptic number.

It is an amenable number.

20218346881 is a deficient number, since it is larger than the sum of its proper divisors (9032319).

20218346881 is an equidigital number, since it uses as much as digits as its factorization.

20218346881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9032318.

The product of its (nonzero) digits is 147456, while the sum is 43.

The spelling of 20218346881 in words is "twenty billion, two hundred eighteen million, three hundred forty-six thousand, eight hundred eighty-one".