66188231 has 4 divisors (see below), whose sum is σ = 66223752. Its totient is φ = 66152712.

The previous prime is 66188219. The next prime is 66188263. The reversal of 66188231 is 13288166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66188231 - 2¹⁸ = 65926087 is a prime.

It is a super-2 number, since 2×66188231² = 8761763845818722, which contains 22 as substring.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a junction number, because it is equal to n+sod(n) for n = 66188191 and 66188200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66188201) 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, 14801 + ... + 18746.

It is an arithmetic number, because the mean of its divisors is an integer number (16555938).

Almost surely, 2^66188231 is an apocalyptic number.

66188231 is a deficient number, since it is larger than the sum of its proper divisors (35521).

66188231 is a wasteful number, since it uses less digits than its factorization.

66188231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35520.

The product of its digits is 13824, while the sum is 35.

The square root of 66188231 is about 8135.6149736821. The cubic root of 66188231 is about 404.5078225866.

The spelling of 66188231 in words is "sixty-six million, one hundred eighty-eight thousand, two hundred thirty-one".