66021191 has 8 divisors (see below), whose sum is σ = 66821040. Its totient is φ = 65225088.

The previous prime is 66021187. The next prime is 66021239. The reversal of 66021191 is 19112066.

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 66021191 - 2² = 66021187 is a prime.

It is a super-2 number, since 2×66021191² = 8717595322116962, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66021191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66021091) 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, 50255 + ... + 51551.

It is an arithmetic number, because the mean of its divisors is an integer number (8352630).

Almost surely, 2^66021191 is an apocalyptic number.

66021191 is a deficient number, since it is larger than the sum of its proper divisors (799849).

66021191 is a wasteful number, since it uses less digits than its factorization.

66021191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1873.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 66021191 is about 8125.3425158574. The cubic root of 66021191 is about 404.1672489074.

The spelling of 66021191 in words is "sixty-six million, twenty-one thousand, one hundred ninety-one".