66616973 has 4 divisors (see below), whose sum is σ = 68914140. Its totient is φ = 64319808.

The previous prime is 66616943. The next prime is 66617017. The reversal of 66616973 is 37961666.

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

It can be written as a sum of positive squares in 2 ways, for example, as 36990724 + 29626249 = 6082^2 + 5443^2 .

It is a cyclic number.

It is not a de Polignac number, because 66616973 - 2¹² = 66612877 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 (66616943) 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, 1148540 + ... + 1148597.

It is an arithmetic number, because the mean of its divisors is an integer number (17228535).

Almost surely, 2^66616973 is an apocalyptic number.

It is an amenable number.

66616973 is a deficient number, since it is larger than the sum of its proper divisors (2297167).

66616973 is a wasteful number, since it uses less digits than its factorization.

66616973 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2297166.

The product of its digits is 244944, while the sum is 44.

The square root of 66616973 is about 8161.9221388102. The cubic root of 66616973 is about 405.3793590221.

The spelling of 66616973 in words is "sixty-six million, six hundred sixteen thousand, nine hundred seventy-three".