53781781 has 2 divisors, whose sum is σ = 53781782. Its totient is φ = 53781780.

The previous prime is 53781779. The next prime is 53781787. The reversal of 53781781 is 18718735.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 43758225 + 10023556 = 6615^2 + 3166^2 .

It is a cyclic number.

It is not a de Polignac number, because 53781781 - 2¹ = 53781779 is a prime.

It is a super-2 number, since 2×53781781² = 5784959935063922, which contains 22 as substring.

Together with 53781779, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (53781787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 26890890 + 26890891.

It is an arithmetic number, because the mean of its divisors is an integer number (26890891).

Almost surely, 2^53781781 is an apocalyptic number.

It is an amenable number.

53781781 is a deficient number, since it is larger than the sum of its proper divisors (1).

53781781 is an equidigital number, since it uses as much as digits as its factorization.

53781781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 47040, while the sum is 40.

The square root of 53781781 is about 7333.6062752237. The cubic root of 53781781 is about 377.4664818273.

The spelling of 53781781 in words is "fifty-three million, seven hundred eighty-one thousand, seven hundred eighty-one".