66949679 has 4 divisors (see below), whose sum is σ = 68582640. Its totient is φ = 65316720.

The previous prime is 66949669. The next prime is 66949681. The reversal of 66949679 is 97694966.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97694966 = 2 ⋅48847483.

It is a cyclic number.

It is not a de Polignac number, because 66949679 - 2¹² = 66945583 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66949609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 816419 + ... + 816500.

It is an arithmetic number, because the mean of its divisors is an integer number (17145660).

Almost surely, 2^66949679 is an apocalyptic number.

66949679 is a deficient number, since it is larger than the sum of its proper divisors (1632961).

66949679 is a wasteful number, since it uses less digits than its factorization.

66949679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1632960.

The product of its digits is 4408992, while the sum is 56.

The square root of 66949679 is about 8182.2783501907. The cubic root of 66949679 is about 406.0531024074.

The spelling of 66949679 in words is "sixty-six million, nine hundred forty-nine thousand, six hundred seventy-nine".