66921169 has 4 divisors (see below), whose sum is σ = 76481344. Its totient is φ = 57360996.

The previous prime is 66921161. The next prime is 66921187. The reversal of 66921169 is 96112966.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 66921169 - 2³ = 66921161 is a prime.

It is a super-2 number, since 2×66921169² = 8956885720653122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66921161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4780077 + ... + 4780090.

It is an arithmetic number, because the mean of its divisors is an integer number (19120336).

Almost surely, 2^66921169 is an apocalyptic number.

It is an amenable number.

66921169 is a deficient number, since it is larger than the sum of its proper divisors (9560175).

66921169 is an equidigital number, since it uses as much as digits as its factorization.

66921169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9560174.

The product of its digits is 34992, while the sum is 40.

The square root of 66921169 is about 8180.5359848851. The cubic root of 66921169 is about 405.9954560388.

The spelling of 66921169 in words is "sixty-six million, nine hundred twenty-one thousand, one hundred sixty-nine".