21138542753 has 2 divisors, whose sum is σ = 21138542754. Its totient is φ = 21138542752.

The previous prime is 21138542717. The next prime is 21138542759. The reversal of 21138542753 is 35724583112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17641949329 + 3496593424 = 132823^2 + 59132^2 .

It is a cyclic number.

It is not a de Polignac number, because 21138542753 - 2²⁰ = 21137494177 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21138542753.

It is not a weakly prime, because it can be changed into another prime (21138542759) 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 as a sum of consecutive naturals, namely, 10569271376 + 10569271377.

It is an arithmetic number, because the mean of its divisors is an integer number (10569271377).

Almost surely, 2^21138542753 is an apocalyptic number.

It is an amenable number.

21138542753 is a deficient number, since it is larger than the sum of its proper divisors (1).

21138542753 is an equidigital number, since it uses as much as digits as its factorization.

21138542753 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 201600, while the sum is 41.

The spelling of 21138542753 in words is "twenty-one billion, one hundred thirty-eight million, five hundred forty-two thousand, seven hundred fifty-three".