21426541 has 2 divisors, whose sum is σ = 21426542. Its totient is φ = 21426540.

The previous prime is 21426521. The next prime is 21426553. The reversal of 21426541 is 14562412.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21353641 + 72900 = 4621^2 + 270^2 .

It is a cyclic number.

It is not a de Polignac number, because 21426541 - 2⁷ = 21426413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21426521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10713270 + 10713271.

It is an arithmetic number, because the mean of its divisors is an integer number (10713271).

Almost surely, 2^21426541 is an apocalyptic number.

It is an amenable number.

21426541 is a deficient number, since it is larger than the sum of its proper divisors (1).

21426541 is an equidigital number, since it uses as much as digits as its factorization.

21426541 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1920, while the sum is 25.

The square root of 21426541 is about 4628.8811823161. The cubic root of 21426541 is about 277.7478390785.

Adding to 21426541 its reverse (14562412), we get a palindrome (35988953).

The spelling of 21426541 in words is "twenty-one million, four hundred twenty-six thousand, five hundred forty-one".