66808831 has 2 divisors, whose sum is σ = 66808832. Its totient is φ = 66808830.

The previous prime is 66808783. The next prime is 66808843. The reversal of 66808831 is 13880866.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66808831 - 2¹⁵ = 66776063 is a prime.

It is a super-2 number, since 2×66808831² = 8926839799173122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66808871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33404415 + 33404416.

It is an arithmetic number, because the mean of its divisors is an integer number (33404416).

Almost surely, 2^66808831 is an apocalyptic number.

66808831 is a deficient number, since it is larger than the sum of its proper divisors (1).

66808831 is an equidigital number, since it uses as much as digits as its factorization.

66808831 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 55296, while the sum is 40.

The square root of 66808831 is about 8173.6669249487. Note that the first 3 decimals coincide. The cubic root of 66808831 is about 405.7681524687.

The spelling of 66808831 in words is "sixty-six million, eight hundred eight thousand, eight hundred thirty-one".