66837921 has 8 divisors (see below), whose sum is σ = 89258400. Its totient is φ = 44488032.

The previous prime is 66837917. The next prime is 66837923. The reversal of 66837921 is 12973866.

It is a happy number.

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

It is not a de Polignac number, because 66837921 - 2² = 66837917 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (66837923) 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, 15396 + ... + 19253.

It is an arithmetic number, because the mean of its divisors is an integer number (11157300).

Almost surely, 2^66837921 is an apocalyptic number.

It is an amenable number.

66837921 is a deficient number, since it is larger than the sum of its proper divisors (22420479).

66837921 is a wasteful number, since it uses less digits than its factorization.

66837921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35295.

The product of its digits is 108864, while the sum is 42.

The square root of 66837921 is about 8175.4462263536. The cubic root of 66837921 is about 405.8270373126.

The spelling of 66837921 in words is "sixty-six million, eight hundred thirty-seven thousand, nine hundred twenty-one".