21541121253 has 6 divisors (see below), whose sum is σ = 31114952934. Its totient is φ = 14360747496.

The previous prime is 21541121171. The next prime is 21541121257. The reversal of 21541121253 is 35212114512.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 17381258244 + 4159863009 = 131838^2 + 64497^2 .

It is not a de Polignac number, because 21541121253 - 2¹⁴ = 21541104869 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21541121257) 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 5 ways as a sum of consecutive naturals, for example, 1196728950 + ... + 1196728967.

It is an arithmetic number, because the mean of its divisors is an integer number (5185825489).

Almost surely, 2^21541121253 is an apocalyptic number.

It is an amenable number.

21541121253 is a deficient number, since it is larger than the sum of its proper divisors (9573831681).

21541121253 is a wasteful number, since it uses less digits than its factorization.

21541121253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2393457923 (or 2393457920 counting only the distinct ones).

The product of its digits is 2400, while the sum is 27.

Adding to 21541121253 its reverse (35212114512), we get a palindrome (56753235765).

The spelling of 21541121253 in words is "twenty-one billion, five hundred forty-one million, one hundred twenty-one thousand, two hundred fifty-three".