66690091 has 8 divisors (see below), whose sum is σ = 71898624. Its totient is φ = 61492800.

The previous prime is 66690089. The next prime is 66690097. The reversal of 66690091 is 19009666.

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 66690091 - 2¹ = 66690089 is a prime.

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 66690091.

It is not an unprimeable number, because it can be changed into a prime (66690097) 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, 12735 + ... + 17191.

It is an arithmetic number, because the mean of its divisors is an integer number (8987328).

Almost surely, 2^66690091 is an apocalyptic number.

66690091 is a deficient number, since it is larger than the sum of its proper divisors (5208533).

66690091 is a wasteful number, since it uses less digits than its factorization.

66690091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5621.

The product of its (nonzero) digits is 17496, while the sum is 37.

The square root of 66690091 is about 8166.4001249020. The cubic root of 66690091 is about 405.5276179861.

The spelling of 66690091 in words is "sixty-six million, six hundred ninety thousand, ninety-one".