66515061553 has 2 divisors, whose sum is σ = 66515061554. Its totient is φ = 66515061552.

The previous prime is 66515061539. The next prime is 66515061589. The reversal of 66515061553 is 35516051566.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40130906929 + 26384154624 = 200327^2 + 162432^2 .

It is a cyclic number.

It is not a de Polignac number, because 66515061553 - 2⁵ = 66515061521 is a prime.

It is not a weakly prime, because it can be changed into another prime (66515061953) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33257530776 + 33257530777.

It is an arithmetic number, because the mean of its divisors is an integer number (33257530777).

Almost surely, 2^66515061553 is an apocalyptic number.

It is an amenable number.

66515061553 is a deficient number, since it is larger than the sum of its proper divisors (1).

66515061553 is an equidigital number, since it uses as much as digits as its factorization.

66515061553 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 405000, while the sum is 43.

The spelling of 66515061553 in words is "sixty-six billion, five hundred fifteen million, sixty-one thousand, five hundred fifty-three".