66278831 has 2 divisors, whose sum is σ = 66278832. Its totient is φ = 66278830.

The previous prime is 66278813. The next prime is 66278851. The reversal of 66278831 is 13887266.

It is a happy number.

Together with previous prime (66278813) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66278831 is a prime.

It is a super-2 number, since 2×66278831² = 8785766877453122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66278851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33139415 + 33139416.

It is an arithmetic number, because the mean of its divisors is an integer number (33139416).

Almost surely, 2^66278831 is an apocalyptic number.

66278831 is a deficient number, since it is larger than the sum of its proper divisors (1).

66278831 is an equidigital number, since it uses as much as digits as its factorization.

66278831 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96768, while the sum is 41.

The square root of 66278831 is about 8141.1811796569. The cubic root of 66278831 is about 404.6923050298.

The spelling of 66278831 in words is "sixty-six million, two hundred seventy-eight thousand, eight hundred thirty-one".