20405227821 has 32 divisors (see below), whose sum is σ = 31772044800. Its totient is φ = 11517324480.

The previous prime is 20405227793. The next prime is 20405227841. The reversal of 20405227821 is 12872250402.

It is not a de Polignac number, because 20405227821 - 2¹⁰ = 20405226797 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20405227841) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 238806 + ... + 312791.

It is an arithmetic number, because the mean of its divisors is an integer number (992876400).

Almost surely, 2^20405227821 is an apocalyptic number.

It is an amenable number.

20405227821 is a deficient number, since it is larger than the sum of its proper divisors (11366816979).

20405227821 is a wasteful number, since it uses less digits than its factorization.

20405227821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 551689.

The product of its (nonzero) digits is 17920, while the sum is 33.

The spelling of 20405227821 in words is "twenty billion, four hundred five million, two hundred twenty-seven thousand, eight hundred twenty-one".