21504235063 has 4 divisors (see below), whose sum is σ = 22245760440. Its totient is φ = 20762709688.

The previous prime is 21504235061. The next prime is 21504235079. The reversal of 21504235063 is 36053240512.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21504235063 - 2¹ = 21504235061 is a prime.

It is a super-2 number, since 2×21504235063² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21504235061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 370762645 + ... + 370762702.

It is an arithmetic number, because the mean of its divisors is an integer number (5561440110).

Almost surely, 2^21504235063 is an apocalyptic number.

21504235063 is a deficient number, since it is larger than the sum of its proper divisors (741525377).

21504235063 is an equidigital number, since it uses as much as digits as its factorization.

21504235063 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 741525376.

The product of its (nonzero) digits is 21600, while the sum is 31.

Adding to 21504235063 its reverse (36053240512), we get a palindrome (57557475575).

The spelling of 21504235063 in words is "twenty-one billion, five hundred four million, two hundred thirty-five thousand, sixty-three".