65071781 has 2 divisors, whose sum is σ = 65071782. Its totient is φ = 65071780.

The previous prime is 65071777. The next prime is 65071817. The reversal of 65071781 is 18717056.

Together with next prime (65071817) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65044225 + 27556 = 8065^2 + 166^2 .

It is a cyclic number.

It is not a de Polignac number, because 65071781 - 2² = 65071777 is a prime.

It is a super-2 number, since 2×65071781² = 8468673365023922, 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 (65071711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32535890 + 32535891.

It is an arithmetic number, because the mean of its divisors is an integer number (32535891).

Almost surely, 2^65071781 is an apocalyptic number.

It is an amenable number.

65071781 is a deficient number, since it is larger than the sum of its proper divisors (1).

65071781 is an equidigital number, since it uses as much as digits as its factorization.

65071781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11760, while the sum is 35.

The square root of 65071781 is about 8066.7081885984. The cubic root of 65071781 is about 402.2205274182.

The spelling of 65071781 in words is "sixty-five million, seventy-one thousand, seven hundred eighty-one".