21424177 has 4 divisors (see below), whose sum is σ = 21513316. Its totient is φ = 21335040.

The previous prime is 21424171. The next prime is 21424189. The reversal of 21424177 is 77142412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9480241 + 11943936 = 3079^2 + 3456^2 .

It is a cyclic number.

It is not a de Polignac number, because 21424177 - 2⁷ = 21424049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21424171) 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, 44208 + ... + 44689.

It is an arithmetic number, because the mean of its divisors is an integer number (5378329).

Almost surely, 2^21424177 is an apocalyptic number.

It is an amenable number.

21424177 is a deficient number, since it is larger than the sum of its proper divisors (89139).

21424177 is an equidigital number, since it uses as much as digits as its factorization.

21424177 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89138.

The product of its digits is 3136, while the sum is 28.

The square root of 21424177 is about 4628.6258219908. The cubic root of 21424177 is about 277.7376240211.

Adding to 21424177 its reverse (77142412), we get a palindrome (98566589).

The spelling of 21424177 in words is "twenty-one million, four hundred twenty-four thousand, one hundred seventy-seven".