66561677029156 has 9 divisors (see below), whose sum is σ = 116482963355899. Its totient is φ = 33280830356044.

The previous prime is 66561677029093. The next prime is 66561677029181. The reversal of 66561677029156 is 65192077616566.

The square root of 66561677029156 is 8158534.

It is a perfect power (a square), and thus also a powerful number.

66561677029156 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66561677029091 and 66561677029100.

It is an unprimeable number.

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 2 ways as a sum of consecutive naturals, for example, 14277435 + ... + 18356701.

Almost surely, 2^{66561677029156} is an apocalyptic number.

66561677029156 is the 8158534-th square number.

It is an amenable number.

66561677029156 is a deficient number, since it is larger than the sum of its proper divisors (49921286326743).

66561677029156 is an frugal number, since it uses more digits than its factorization.

66561677029156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8158538 (or 4079269 counting only the distinct ones).

The product of its (nonzero) digits is 171460800, while the sum is 67.

The spelling of 66561677029156 in words is "sixty-six trillion, five hundred sixty-one billion, six hundred seventy-seven million, twenty-nine thousand, one hundred fifty-six".