22118821 has 4 divisors (see below), whose sum is σ = 22182912. Its totient is φ = 22054732.

The previous prime is 22118809. The next prime is 22118839. The reversal of 22118821 is 12881122.

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: 12881122 = 2 ⋅6440561.

It is a cyclic number.

It is not a de Polignac number, because 22118821 - 2⁷ = 22118693 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22118891) 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, 31525 + ... + 32218.

It is an arithmetic number, because the mean of its divisors is an integer number (5545728).

Almost surely, 2^22118821 is an apocalyptic number.

It is an amenable number.

22118821 is a deficient number, since it is larger than the sum of its proper divisors (64091).

22118821 is an equidigital number, since it uses as much as digits as its factorization.

22118821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64090.

The product of its digits is 512, while the sum is 25.

The square root of 22118821 is about 4703.0650644022. The cubic root of 22118821 is about 280.7074838344.

Adding to 22118821 its reverse (12881122), we get a palindrome (34999943).

The spelling of 22118821 in words is "twenty-two million, one hundred eighteen thousand, eight hundred twenty-one".