66409972 has 6 divisors (see below), whose sum is σ = 116217458. Its totient is φ = 33204984.

The previous prime is 66409969. The next prime is 66409979. The reversal of 66409972 is 27990466.

It can be written as a sum of positive squares in only one way, i.e., 44169316 + 22240656 = 6646^2 + 4716^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66409979) 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 as a sum of consecutive naturals, namely, 8301243 + ... + 8301250.

Almost surely, 2^66409972 is an apocalyptic number.

It is an amenable number.

66409972 is a deficient number, since it is larger than the sum of its proper divisors (49807486).

66409972 is a wasteful number, since it uses less digits than its factorization.

66409972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16602497 (or 16602495 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 43.

The square root of 66409972 is about 8149.2313747985. The cubic root of 66409972 is about 404.9590407188.

The spelling of 66409972 in words is "sixty-six million, four hundred nine thousand, nine hundred seventy-two".