73081781 has 2 divisors, whose sum is σ = 73081782. Its totient is φ = 73081780.

The previous prime is 73081747. The next prime is 73081807. The reversal of 73081781 is 18718037.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55726225 + 17355556 = 7465^2 + 4166^2 .

It is a cyclic number.

It is not a de Polignac number, because 73081781 - 2⁶ = 73081717 is a prime.

It is a super-2 number, since 2×73081781² = 10681893428263922, 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 (73083781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36540890 + 36540891.

It is an arithmetic number, because the mean of its divisors is an integer number (36540891).

Almost surely, 2^73081781 is an apocalyptic number.

It is an amenable number.

73081781 is a deficient number, since it is larger than the sum of its proper divisors (1).

73081781 is an equidigital number, since it uses as much as digits as its factorization.

73081781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9408, while the sum is 35.

The square root of 73081781 is about 8548.7882767092. The cubic root of 73081781 is about 418.0899301329.

The spelling of 73081781 in words is "seventy-three million, eighty-one thousand, seven hundred eighty-one".