21256044514253 has 2 divisors, whose sum is σ = 21256044514254. Its totient is φ = 21256044514252.

The previous prime is 21256044514217. The next prime is 21256044514277. The reversal of 21256044514253 is 35241544065212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12202914333289 + 9053130180964 = 3493267^2 + 3008842^2 .

It is a cyclic number.

It is not a de Polignac number, because 21256044514253 - 2³² = 21251749546957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21256044519253) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10628022257126 + 10628022257127.

It is an arithmetic number, because the mean of its divisors is an integer number (10628022257127).

Almost surely, 2^{21256044514253} is an apocalyptic number.

It is an amenable number.

21256044514253 is a deficient number, since it is larger than the sum of its proper divisors (1).

21256044514253 is an equidigital number, since it uses as much as digits as its factorization.

21256044514253 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152000, while the sum is 44.

Adding to 21256044514253 its reverse (35241544065212), we get a palindrome (56497588579465).

The spelling of 21256044514253 in words is "twenty-one trillion, two hundred fifty-six billion, forty-four million, five hundred fourteen thousand, two hundred fifty-three".