66823857 has 12 divisors (see below), whose sum is σ = 97964880. Its totient is φ = 43883928.

The previous prime is 66823837. The next prime is 66823871. The reversal of 66823857 is 75832866.

It is not a de Polignac number, because 66823857 - 2¹⁸ = 66561713 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66823837) 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 11 ways as a sum of consecutive naturals, for example, 54807 + ... + 56012.

It is an arithmetic number, because the mean of its divisors is an integer number (8163740).

Almost surely, 2^66823857 is an apocalyptic number.

66823857 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

It is an amenable number.

66823857 is a deficient number, since it is larger than the sum of its proper divisors (31141023).

66823857 is a wasteful number, since it uses less digits than its factorization.

66823857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110892 (or 110889 counting only the distinct ones).

The product of its digits is 483840, while the sum is 45.

The square root of 66823857 is about 8174.5860445652. The cubic root of 66823857 is about 405.7985706790.

Subtracting 66823857 from its reverse (75832866), we obtain a palindrome (9009009).

The spelling of 66823857 in words is "sixty-six million, eight hundred twenty-three thousand, eight hundred fifty-seven".