66978377387966 has 32 divisors (see below), whose sum is σ = 110689537239936. Its totient is φ = 30142358820000.

The previous prime is 66978377387953. The next prime is 66978377388007.

66978377387966 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×66978377387966² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74682281 + ... + 75573803.

It is an arithmetic number, because the mean of its divisors is an integer number (3459048038748).

Almost surely, 2^{66978377387966} is an apocalyptic number.

66978377387966 is a deficient number, since it is larger than the sum of its proper divisors (43711159851970).

66978377387966 is a wasteful number, since it uses less digits than its factorization.

66978377387966 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 925448.

The product of its digits is 145179288576, while the sum is 92.

The spelling of 66978377387966 in words is "sixty-six trillion, nine hundred seventy-eight billion, three hundred seventy-seven million, three hundred eighty-seven thousand, nine hundred sixty-six".