66921208 has 16 divisors (see below), whose sum is σ = 127351080. Its totient is φ = 32960928.

The previous prime is 66921203. The next prime is 66921221. The reversal of 66921208 is 80212966.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66921203) 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, 61891 + ... + 62962.

Almost surely, 2^66921208 is an apocalyptic number.

It is an amenable number.

66921208 is a deficient number, since it is larger than the sum of its proper divisors (60429872).

66921208 is a wasteful number, since it uses less digits than its factorization.

66921208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124926 (or 124922 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 66921208 is about 8180.5383685916. The cubic root of 66921208 is about 405.9955349069.

The spelling of 66921208 in words is "sixty-six million, nine hundred twenty-one thousand, two hundred eight".