21226577 has 4 divisors (see below), whose sum is σ = 21238116. Its totient is φ = 21215040.

The previous prime is 21226571. The next prime is 21226603. The reversal of 21226577 is 77562212.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 17048641 + 4177936 = 4129^2 + 2044^2 .

It is a cyclic number.

It is not a de Polignac number, because 21226577 - 2⁸ = 21226321 is a prime.

It is a super-2 number, since 2×21226577² = 901135142273858, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21226571) 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, 2324 + ... + 6917.

It is an arithmetic number, because the mean of its divisors is an integer number (5309529).

Almost surely, 2^21226577 is an apocalyptic number.

It is an amenable number.

21226577 is a deficient number, since it is larger than the sum of its proper divisors (11539).

21226577 is an equidigital number, since it uses as much as digits as its factorization.

21226577 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11538.

The product of its digits is 11760, while the sum is 32.

The square root of 21226577 is about 4607.2309471091. The cubic root of 21226577 is about 276.8811064697.

Adding to 21226577 its reverse (77562212), we get a palindrome (98788789).

The spelling of 21226577 in words is "twenty-one million, two hundred twenty-six thousand, five hundred seventy-seven".