21351251333 has 4 divisors (see below), whose sum is σ = 22040001408. Its totient is φ = 20662501260.

The previous prime is 21351251329. The next prime is 21351251353. The reversal of 21351251333 is 33315215312.

It is a happy number.

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 21351251333 - 2² = 21351251329 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21351251296 and 21351251305.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21351251353) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 344374991 + ... + 344375052.

It is an arithmetic number, because the mean of its divisors is an integer number (5510000352).

Almost surely, 2^21351251333 is an apocalyptic number.

It is an amenable number.

21351251333 is a deficient number, since it is larger than the sum of its proper divisors (688750075).

21351251333 is an equidigital number, since it uses as much as digits as its factorization.

21351251333 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 688750074.

The product of its digits is 8100, while the sum is 29.

Adding to 21351251333 its reverse (33315215312), we get a palindrome (54666466645).

The spelling of 21351251333 in words is "twenty-one billion, three hundred fifty-one million, two hundred fifty-one thousand, three hundred thirty-three".