67906781 has 2 divisors, whose sum is σ = 67906782. Its totient is φ = 67906780.

The previous prime is 67906759. The next prime is 67906799. The reversal of 67906781 is 18760976.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67404100 + 502681 = 8210^2 + 709^2 .

It is a cyclic number.

It is not a de Polignac number, because 67906781 - 2²² = 63712477 is a prime.

It is a super-2 number, since 2×67906781² = 9222661811563922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (67906981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33953390 + 33953391.

It is an arithmetic number, because the mean of its divisors is an integer number (33953391).

Almost surely, 2^67906781 is an apocalyptic number.

It is an amenable number.

67906781 is a deficient number, since it is larger than the sum of its proper divisors (1).

67906781 is an equidigital number, since it uses as much as digits as its factorization.

67906781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 127008, while the sum is 44.

The square root of 67906781 is about 8240.5570806833. The cubic root of 67906781 is about 407.9789112674.

The spelling of 67906781 in words is "sixty-seven million, nine hundred six thousand, seven hundred eighty-one".