66212651677 has 2 divisors, whose sum is σ = 66212651678. Its totient is φ = 66212651676.

The previous prime is 66212651639. The next prime is 66212651717. The reversal of 66212651677 is 77615621266.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47765850916 + 18446800761 = 218554^2 + 135819^2 .

It is a cyclic number.

It is not a de Polignac number, because 66212651677 - 2³¹ = 64065168029 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66212651677.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66212651627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33106325838 + 33106325839.

It is an arithmetic number, because the mean of its divisors is an integer number (33106325839).

Almost surely, 2^66212651677 is an apocalyptic number.

It is an amenable number.

66212651677 is a deficient number, since it is larger than the sum of its proper divisors (1).

66212651677 is an equidigital number, since it uses as much as digits as its factorization.

66212651677 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1270080, while the sum is 49.

The spelling of 66212651677 in words is "sixty-six billion, two hundred twelve million, six hundred fifty-one thousand, six hundred seventy-seven".