66490921 has 8 divisors (see below), whose sum is σ = 76844160. Its totient is φ = 56351328.

The previous prime is 66490909. The next prime is 66490933. The reversal of 66490921 is 12909466.

It is an interprime number because it is at equal distance from previous prime (66490909) and next prime (66490933).

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

It is a cyclic number.

It is not a de Polignac number, because 66490921 - 2⁹ = 66490409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66490951) 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, 52741 + ... + 53986.

It is an arithmetic number, because the mean of its divisors is an integer number (9605520).

Almost surely, 2^66490921 is an apocalyptic number.

It is an amenable number.

66490921 is a deficient number, since it is larger than the sum of its proper divisors (10353239).

66490921 is a wasteful number, since it uses less digits than its factorization.

66490921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106823.

The product of its (nonzero) digits is 23328, while the sum is 37.

The square root of 66490921 is about 8154.1965269424. The cubic root of 66490921 is about 405.1235126004.

The spelling of 66490921 in words is "sixty-six million, four hundred ninety thousand, nine hundred twenty-one".