23221661 has 4 divisors (see below), whose sum is σ = 23232000. Its totient is φ = 23211324.

The previous prime is 23221631. The next prime is 23221669. The reversal of 23221661 is 16612232.

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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 23221661 - 2¹⁴ = 23205277 is a prime.

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 (23221669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 221 + ... + 6818.

It is an arithmetic number, because the mean of its divisors is an integer number (5808000).

Almost surely, 2^23221661 is an apocalyptic number.

It is an amenable number.

23221661 is a deficient number, since it is larger than the sum of its proper divisors (10339).

23221661 is an equidigital number, since it uses as much as digits as its factorization.

23221661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10338.

The product of its digits is 864, while the sum is 23.

The square root of 23221661 is about 4818.8858670859. The cubic root of 23221661 is about 285.2973648081.

Adding to 23221661 its reverse (16612232), we get a palindrome (39833893).

The spelling of 23221661 in words is "twenty-three million, two hundred twenty-one thousand, six hundred sixty-one".