21530351351 has 4 divisors (see below), whose sum is σ = 21530983752. Its totient is φ = 21529718952.

The previous prime is 21530351341. The next prime is 21530351363. The reversal of 21530351351 is 15315303512.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21530351351 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 (21530351341) 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, 262040 + ... + 334253.

It is an arithmetic number, because the mean of its divisors is an integer number (5382745938).

Almost surely, 2^21530351351 is an apocalyptic number.

21530351351 is a deficient number, since it is larger than the sum of its proper divisors (632401).

21530351351 is an equidigital number, since it uses as much as digits as its factorization.

21530351351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 632400.

The product of its (nonzero) digits is 6750, while the sum is 29.

Adding to 21530351351 its reverse (15315303512), we get a palindrome (36845654863).

The spelling of 21530351351 in words is "twenty-one billion, five hundred thirty million, three hundred fifty-one thousand, three hundred fifty-one".