22121521 has 2 divisors, whose sum is σ = 22121522. Its totient is φ = 22121520.

The previous prime is 22121513. The next prime is 22121531. The reversal of 22121521 is 12512122.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16289296 + 5832225 = 4036^2 + 2415^2 .

It is a cyclic number.

It is not a de Polignac number, because 22121521 - 2³ = 22121513 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 22121495 and 22121504.

It is not a weakly prime, because it can be changed into another prime (22121531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11060760 + 11060761.

It is an arithmetic number, because the mean of its divisors is an integer number (11060761).

Almost surely, 2^22121521 is an apocalyptic number.

It is an amenable number.

22121521 is a deficient number, since it is larger than the sum of its proper divisors (1).

22121521 is an equidigital number, since it uses as much as digits as its factorization.

22121521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 80, while the sum is 16.

The square root of 22121521 is about 4703.3521024903. The cubic root of 22121521 is about 280.7189051690.

Adding to 22121521 its reverse (12512122), we get a palindrome (34633643).

The spelling of 22121521 in words is "twenty-two million, one hundred twenty-one thousand, five hundred twenty-one".