22431521 has 4 divisors (see below), whose sum is σ = 25636032. Its totient is φ = 19227012.

The previous prime is 22431473. The next prime is 22431559. The reversal of 22431521 is 12513422.

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.

It is a de Polignac number, because none of the positive numbers 2^k-22431521 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 22431493 and 22431502.

It is not an unprimeable number, because it can be changed into a prime (22431821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1602245 + ... + 1602258.

It is an arithmetic number, because the mean of its divisors is an integer number (6409008).

Almost surely, 2^22431521 is an apocalyptic number.

It is an amenable number.

22431521 is a deficient number, since it is larger than the sum of its proper divisors (3204511).

22431521 is an equidigital number, since it uses as much as digits as its factorization.

22431521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3204510.

The product of its digits is 480, while the sum is 20.

The square root of 22431521 is about 4736.1926692228. The cubic root of 22431521 is about 282.0241122517.

Adding to 22431521 its reverse (12513422), we get a palindrome (34944943).

The spelling of 22431521 in words is "twenty-two million, four hundred thirty-one thousand, five hundred twenty-one".