21253100262553 has 4 divisors (see below), whose sum is σ = 21544238622388. Its totient is φ = 20961961902720.

The previous prime is 21253100262509. The next prime is 21253100262599. The reversal of 21253100262553 is 35526200135212.

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

It can be written as a sum of positive squares in 2 ways, for example, as 13669228684864 + 7583871577689 = 3697192^2 + 2753883^2 .

It is a cyclic number.

It is not a de Polignac number, because 21253100262553 - 2⁹ = 21253100262041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21253100266553) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 145569179808 + ... + 145569179953.

It is an arithmetic number, because the mean of its divisors is an integer number (5386059655597).

Almost surely, 2^{21253100262553} is an apocalyptic number.

It is an amenable number.

21253100262553 is a deficient number, since it is larger than the sum of its proper divisors (291138359835).

21253100262553 is an equidigital number, since it uses as much as digits as its factorization.

21253100262553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291138359834.

The product of its (nonzero) digits is 108000, while the sum is 37.

Adding to 21253100262553 its reverse (35526200135212), we get a palindrome (56779300397765).

The spelling of 21253100262553 in words is "twenty-one trillion, two hundred fifty-three billion, one hundred million, two hundred sixty-two thousand, five hundred fifty-three".