21255340313 has 4 divisors (see below), whose sum is σ = 22179485568. Its totient is φ = 20331195060.

The previous prime is 21255340307. The next prime is 21255340331. The reversal of 21255340313 is 31304355212.

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 21255340313 - 2⁴ = 21255340297 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21255340303) 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, 462072593 + ... + 462072638.

It is an arithmetic number, because the mean of its divisors is an integer number (5544871392).

Almost surely, 2^21255340313 is an apocalyptic number.

21255340313 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21255340313 is a deficient number, since it is larger than the sum of its proper divisors (924145255).

21255340313 is an equidigital number, since it uses as much as digits as its factorization.

21255340313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 924145254.

The product of its (nonzero) digits is 10800, while the sum is 29.

Adding to 21255340313 its reverse (31304355212), we get a palindrome (52559695525).

The spelling of 21255340313 in words is "twenty-one billion, two hundred fifty-five million, three hundred forty thousand, three hundred thirteen".