66100050053581 has 2 divisors, whose sum is σ = 66100050053582. Its totient is φ = 66100050053580.

The previous prime is 66100050053563. The next prime is 66100050053593. The reversal of 66100050053581 is 18535005000166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 33968906041225 + 32131144012356 = 5828285^2 + 5668434^2 .

It is a cyclic number.

It is not a de Polignac number, because 66100050053581 - 2⁹ = 66100050053069 is a prime.

It is a super-2 number, since 2×66100050053581² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66100050059581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33050025026790 + 33050025026791.

It is an arithmetic number, because the mean of its divisors is an integer number (33050025026791).

Almost surely, 2^{66100050053581} is an apocalyptic number.

It is an amenable number.

66100050053581 is a deficient number, since it is larger than the sum of its proper divisors (1).

66100050053581 is an equidigital number, since it uses as much as digits as its factorization.

66100050053581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108000, while the sum is 40.

The spelling of 66100050053581 in words is "sixty-six trillion, one hundred billion, fifty million, fifty-three thousand, five hundred eighty-one".