21371194553 has 2 divisors, whose sum is σ = 21371194554. Its totient is φ = 21371194552.

The previous prime is 21371194541. The next prime is 21371194567. The reversal of 21371194553 is 35549117312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16865697424 + 4505497129 = 129868^2 + 67123^2 .

It is a cyclic number.

It is not a de Polignac number, because 21371194553 - 2¹² = 21371190457 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21371194553.

It is not a weakly prime, because it can be changed into another prime (21371194573) 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 as a sum of consecutive naturals, namely, 10685597276 + 10685597277.

It is an arithmetic number, because the mean of its divisors is an integer number (10685597277).

Almost surely, 2^21371194553 is an apocalyptic number.

It is an amenable number.

21371194553 is a deficient number, since it is larger than the sum of its proper divisors (1).

21371194553 is an equidigital number, since it uses as much as digits as its factorization.

21371194553 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 113400, while the sum is 41.

The spelling of 21371194553 in words is "twenty-one billion, three hundred seventy-one million, one hundred ninety-four thousand, five hundred fifty-three".