21088553 has 2 divisors, whose sum is σ = 21088554. Its totient is φ = 21088552.

The previous prime is 21088549. The next prime is 21088559. The reversal of 21088553 is 35588012.

It is a happy number.

21088553 is nontrivially palindromic in base 7.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21049744 + 38809 = 4588^2 + 197^2 .

It is a cyclic number.

It is not a de Polignac number, because 21088553 - 2² = 21088549 is a prime.

It is not a weakly prime, because it can be changed into another prime (21088559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10544276 + 10544277.

It is an arithmetic number, because the mean of its divisors is an integer number (10544277).

Almost surely, 2^21088553 is an apocalyptic number.

It is an amenable number.

21088553 is a deficient number, since it is larger than the sum of its proper divisors (1).

21088553 is an equidigital number, since it uses as much as digits as its factorization.

21088553 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9600, while the sum is 32.

The square root of 21088553 is about 4592.2274551681. The cubic root of 21088553 is about 276.2796690833.

The spelling of 21088553 in words is "twenty-one million, eighty-eight thousand, five hundred fifty-three".