66981907 has 4 divisors (see below), whose sum is σ = 67431600. Its totient is φ = 66532216.

The previous prime is 66981899. The next prime is 66981919. The reversal of 66981907 is 70918966.

66981907 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66981907 - 2³ = 66981899 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66981947) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 224623 + ... + 224920.

It is an arithmetic number, because the mean of its divisors is an integer number (16857900).

Almost surely, 2^66981907 is an apocalyptic number.

66981907 is a deficient number, since it is larger than the sum of its proper divisors (449693).

66981907 is a wasteful number, since it uses less digits than its factorization.

66981907 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 449692.

The product of its (nonzero) digits is 163296, while the sum is 46.

The square root of 66981907 is about 8184.2474913702. The cubic root of 66981907 is about 406.1182467582.

The spelling of 66981907 in words is "sixty-six million, nine hundred eighty-one thousand, nine hundred seven".