22812021821 has 4 divisors (see below), whose sum is σ = 22815509532. Its totient is φ = 22808534112.

The previous prime is 22812021803. The next prime is 22812021823. The reversal of 22812021821 is 12812021822.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15100723225 + 7711298596 = 122885^2 + 87814^2 .

It is a cyclic number.

It is not a de Polignac number, because 22812021821 - 2²² = 22807827517 is a prime.

It is a super-3 number, since 3×22812021821³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22812021823) 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, 1734026 + ... + 1747131.

It is an arithmetic number, because the mean of its divisors is an integer number (5703877383).

Almost surely, 2^22812021821 is an apocalyptic number.

It is an amenable number.

22812021821 is a deficient number, since it is larger than the sum of its proper divisors (3487711).

22812021821 is an equidigital number, since it uses as much as digits as its factorization.

22812021821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3487710.

The product of its (nonzero) digits is 2048, while the sum is 29.

Subtracting from 22812021821 its reverse (12812021822), we obtain a palindrome (9999999999).

The spelling of 22812021821 in words is "twenty-two billion, eight hundred twelve million, twenty-one thousand, eight hundred twenty-one".