21426553 has 2 divisors, whose sum is σ = 21426554. Its totient is φ = 21426552.

The previous prime is 21426541. The next prime is 21426583. The reversal of 21426553 is 35562412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21409129 + 17424 = 4627^2 + 132^2 .

It is a cyclic number.

It is not a de Polignac number, because 21426553 - 2⁵ = 21426521 is a prime.

It is not a weakly prime, because it can be changed into another prime (21426583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10713276 + 10713277.

It is an arithmetic number, because the mean of its divisors is an integer number (10713277).

Almost surely, 2^21426553 is an apocalyptic number.

It is an amenable number.

21426553 is a deficient number, since it is larger than the sum of its proper divisors (1).

21426553 is an equidigital number, since it uses as much as digits as its factorization.

21426553 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7200, while the sum is 28.

The square root of 21426553 is about 4628.8824785255. The cubic root of 21426553 is about 277.7478909297.

Adding to 21426553 its reverse (35562412), we get a palindrome (56988965).

The spelling of 21426553 in words is "twenty-one million, four hundred twenty-six thousand, five hundred fifty-three".