21126321053 has 4 divisors (see below), whose sum is σ = 21127084608. Its totient is φ = 21125557500.

The previous prime is 21126321017. The next prime is 21126321089. The reversal of 21126321053 is 35012362112.

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 an interprime number because it is at equal distance from previous prime (21126321017) and next prime (21126321089).

It is a cyclic number.

It is not a de Polignac number, because 21126321053 - 2¹⁸ = 21126058909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21126324053) 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 3 ways as a sum of consecutive naturals, for example, 338651 + ... + 396152.

It is an arithmetic number, because the mean of its divisors is an integer number (5281771152).

Almost surely, 2^21126321053 is an apocalyptic number.

It is an amenable number.

21126321053 is a deficient number, since it is larger than the sum of its proper divisors (763555).

21126321053 is an equidigital number, since it uses as much as digits as its factorization.

21126321053 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 763554.

The product of its (nonzero) digits is 2160, while the sum is 26.

Adding to 21126321053 its reverse (35012362112), we get a palindrome (56138683165).

The spelling of 21126321053 in words is "twenty-one billion, one hundred twenty-six million, three hundred twenty-one thousand, fifty-three".