21252563 has 8 divisors (see below), whose sum is σ = 22288800. Its totient is φ = 20236608.

The previous prime is 21252551. The next prime is 21252571. The reversal of 21252563 is 36525212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21252563 - 2⁴ = 21252547 is a prime.

It is a super-3 number, since 3×21252563³ (a number of 23 digits) contains 333 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21252503) 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 7 ways as a sum of consecutive naturals, for example, 2903 + ... + 7136.

It is an arithmetic number, because the mean of its divisors is an integer number (2786100).

Almost surely, 2^21252563 is an apocalyptic number.

21252563 is a deficient number, since it is larger than the sum of its proper divisors (1036237).

21252563 is a wasteful number, since it uses less digits than its factorization.

21252563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10141.

The product of its digits is 3600, while the sum is 26.

The square root of 21252563 is about 4610.0502166462. The cubic root of 21252563 is about 276.9940481894.

Adding to 21252563 its reverse (36525212), we get a palindrome (57777775).

The spelling of 21252563 in words is "twenty-one million, two hundred fifty-two thousand, five hundred sixty-three".