21553985104537 has 2 divisors, whose sum is σ = 21553985104538. Its totient is φ = 21553985104536.

The previous prime is 21553985104471. The next prime is 21553985104549. The reversal of 21553985104537 is 73540158935512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18290539241536 + 3263445863001 = 4276744^2 + 1806501^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21553985104537 is a prime.

It is not a weakly prime, because it can be changed into another prime (21553985104237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10776992552268 + 10776992552269.

It is an arithmetic number, because the mean of its divisors is an integer number (10776992552269).

Almost surely, 2^{21553985104537} is an apocalyptic number.

It is an amenable number.

21553985104537 is a deficient number, since it is larger than the sum of its proper divisors (1).

21553985104537 is an equidigital number, since it uses as much as digits as its factorization.

21553985104537 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 22680000, while the sum is 58.

The spelling of 21553985104537 in words is "twenty-one trillion, five hundred fifty-three billion, nine hundred eighty-five million, one hundred four thousand, five hundred thirty-seven".