30768781 has 2 divisors, whose sum is σ = 30768782. Its totient is φ = 30768780.

The previous prime is 30768769. The next prime is 30768791. The reversal of 30768781 is 18786703.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27405225 + 3363556 = 5235^2 + 1834^2 .

It is a cyclic number.

It is not a de Polignac number, because 30768781 - 2¹³ = 30760589 is a prime.

It is a super-2 number, since 2×30768781² = 1893435768451922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (30768761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15384390 + 15384391.

It is an arithmetic number, because the mean of its divisors is an integer number (15384391).

Almost surely, 2^30768781 is an apocalyptic number.

It is an amenable number.

30768781 is a deficient number, since it is larger than the sum of its proper divisors (1).

30768781 is an equidigital number, since it uses as much as digits as its factorization.

30768781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 56448, while the sum is 40.

The square root of 30768781 is about 5546.9614204535. The cubic root of 30768781 is about 313.3550972006.

The spelling of 30768781 in words is "thirty million, seven hundred sixty-eight thousand, seven hundred eighty-one".