22118721 has 8 divisors (see below), whose sum is σ = 30211104. Its totient is φ = 14386080.

The previous prime is 22118713. The next prime is 22118729. The reversal of 22118721 is 12781122.

It is an interprime number because it is at equal distance from previous prime (22118713) and next prime (22118729).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 22118721 - 2³ = 22118713 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 22118691 and 22118700.

It is not an unprimeable number, because it can be changed into a prime (22118729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 89791 + ... + 90036.

It is an arithmetic number, because the mean of its divisors is an integer number (3776388).

Almost surely, 2^22118721 is an apocalyptic number.

It is an amenable number.

22118721 is a deficient number, since it is larger than the sum of its proper divisors (8092383).

22118721 is a wasteful number, since it uses less digits than its factorization.

22118721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 179871.

The product of its digits is 448, while the sum is 24.

The square root of 22118721 is about 4703.0544330254. The cubic root of 22118721 is about 280.7070608041.

Adding to 22118721 its reverse (12781122), we get a palindrome (34899843).

The spelling of 22118721 in words is "twenty-two million, one hundred eighteen thousand, seven hundred twenty-one".