21530245043 has 4 divisors (see below), whose sum is σ = 21743415888. Its totient is φ = 21317074200.

The previous prime is 21530245031. The next prime is 21530245081. The reversal of 21530245043 is 34054203512.

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 21530245043 - 2⁶ = 21530244979 is a prime.

It is a super-2 number, since 2×21530245043² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21530244997 and 21530245015.

It is not an unprimeable number, because it can be changed into a prime (21530245003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106585271 + ... + 106585472.

It is an arithmetic number, because the mean of its divisors is an integer number (5435853972).

Almost surely, 2^21530245043 is an apocalyptic number.

21530245043 is a deficient number, since it is larger than the sum of its proper divisors (213170845).

21530245043 is a wasteful number, since it uses less digits than its factorization.

21530245043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213170844.

The product of its (nonzero) digits is 14400, while the sum is 29.

Adding to 21530245043 its reverse (34054203512), we get a palindrome (55584448555).

The spelling of 21530245043 in words is "twenty-one billion, five hundred thirty million, two hundred forty-five thousand, forty-three".