66672921 has 8 divisors (see below), whose sum is σ = 101596864. Its totient is φ = 38098800.

The previous prime is 66672899. The next prime is 66672923. The reversal of 66672921 is 12927666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66672921 - 2⁵ = 66672889 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 66672921.

It is not an unprimeable number, because it can be changed into a prime (66672923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1587430 + ... + 1587471.

It is an arithmetic number, because the mean of its divisors is an integer number (12699608).

Almost surely, 2^66672921 is an apocalyptic number.

It is an amenable number.

66672921 is a deficient number, since it is larger than the sum of its proper divisors (34923943).

66672921 is a wasteful number, since it uses less digits than its factorization.

66672921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3174911.

The product of its digits is 54432, while the sum is 39.

The square root of 66672921 is about 8165.3487984286. The cubic root of 66672921 is about 405.4928126813.

The spelling of 66672921 in words is "sixty-six million, six hundred seventy-two thousand, nine hundred twenty-one".