66540823 has 8 divisors (see below), whose sum is σ = 68381456. Its totient is φ = 64713600.

The previous prime is 66540821. The next prime is 66540833. The reversal of 66540823 is 32804566.

It is a happy number.

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 66540823 - 2¹ = 66540821 is a prime.

It is a super-2 number, since 2×66540823² = 8855362251034658, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66540821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7153 + ... + 13573.

It is an arithmetic number, because the mean of its divisors is an integer number (8547682).

Almost surely, 2^66540823 is an apocalyptic number.

66540823 is a deficient number, since it is larger than the sum of its proper divisors (1840633).

66540823 is a wasteful number, since it uses less digits than its factorization.

66540823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6705.

The product of its (nonzero) digits is 34560, while the sum is 34.

The square root of 66540823 is about 8157.2558498554. The cubic root of 66540823 is about 405.2248368002.

The spelling of 66540823 in words is "sixty-six million, five hundred forty thousand, eight hundred twenty-three".