66511567690 has 16 divisors (see below), whose sum is σ = 119761198920. Its totient is φ = 26595654400.

The previous prime is 66511567651. The next prime is 66511567691. The reversal of 66511567690 is 9676511566.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 23018048089 + 43493519601 = 151717^2 + 208551^2 .

It is a super-2 number, since 2×66511567690² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66511567691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1090411 + ... + 1149790.

Almost surely, 2^66511567690 is an apocalyptic number.

66511567690 is a deficient number, since it is larger than the sum of its proper divisors (53249631230).

66511567690 is a wasteful number, since it uses less digits than its factorization.

66511567690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2243177.

The product of its (nonzero) digits is 2041200, while the sum is 52.

The spelling of 66511567690 in words is "sixty-six billion, five hundred eleven million, five hundred sixty-seven thousand, six hundred ninety".