21530152021 has 4 divisors (see below), whose sum is σ = 24605888032. Its totient is φ = 18454416012.

The previous prime is 21530152013. The next prime is 21530152057. The reversal of 21530152021 is 12025103512.

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 21530152021 - 2³ = 21530152013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21530151983 and 21530152001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21530152621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1537867995 + ... + 1537868008.

It is an arithmetic number, because the mean of its divisors is an integer number (6151472008).

Almost surely, 2^21530152021 is an apocalyptic number.

It is an amenable number.

21530152021 is a deficient number, since it is larger than the sum of its proper divisors (3075736011).

21530152021 is an equidigital number, since it uses as much as digits as its factorization.

21530152021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3075736010.

The product of its (nonzero) digits is 600, while the sum is 22.

Adding to 21530152021 its reverse (12025103512), we get a palindrome (33555255533).

The spelling of 21530152021 in words is "twenty-one billion, five hundred thirty million, one hundred fifty-two thousand, twenty-one".