21063557 has 4 divisors (see below), whose sum is σ = 21156576. Its totient is φ = 20970540.

The previous prime is 21063529. The next prime is 21063569. The reversal of 21063557 is 75536012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21063557 - 2¹² = 21059461 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21063517) 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, 46169 + ... + 46622.

It is an arithmetic number, because the mean of its divisors is an integer number (5289144).

Almost surely, 2^21063557 is an apocalyptic number.

It is an amenable number.

21063557 is a deficient number, since it is larger than the sum of its proper divisors (93019).

21063557 is an equidigital number, since it uses as much as digits as its factorization.

21063557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93018.

The product of its (nonzero) digits is 6300, while the sum is 29.

The square root of 21063557 is about 4589.5050931446. The cubic root of 21063557 is about 276.1704689738.

Adding to 21063557 its reverse (75536012), we get a palindrome (96599569).

The spelling of 21063557 in words is "twenty-one million, sixty-three thousand, five hundred fifty-seven".