22153721 has 4 divisors (see below), whose sum is σ = 22170000. Its totient is φ = 22137444.

The previous prime is 22153717. The next prime is 22153723. The reversal of 22153721 is 12735122.

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: 12735122 = 2 ⋅6367561.

It is a cyclic number.

It is not a de Polignac number, because 22153721 - 2² = 22153717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (22153723) 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, 5891 + ... + 8888.

It is an arithmetic number, because the mean of its divisors is an integer number (5542500).

Almost surely, 2^22153721 is an apocalyptic number.

It is an amenable number.

22153721 is a deficient number, since it is larger than the sum of its proper divisors (16279).

22153721 is a wasteful number, since it uses less digits than its factorization.

22153721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16278.

The product of its digits is 840, while the sum is 23.

The square root of 22153721 is about 4706.7739482580. The cubic root of 22153721 is about 280.8550435853.

Adding to 22153721 its reverse (12735122), we get a palindrome (34888843).

The spelling of 22153721 in words is "twenty-two million, one hundred fifty-three thousand, seven hundred twenty-one".