67878661 has 2 divisors, whose sum is σ = 67878662. Its totient is φ = 67878660.

The previous prime is 67878649. The next prime is 67878689. The reversal of 67878661 is 16687876.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 67338436 + 540225 = 8206^2 + 735^2 .

It is a cyclic number.

It is not a de Polignac number, because 67878661 - 2⁷ = 67878533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (67878631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33939330 + 33939331.

It is an arithmetic number, because the mean of its divisors is an integer number (33939331).

Almost surely, 2^67878661 is an apocalyptic number.

It is an amenable number.

67878661 is a deficient number, since it is larger than the sum of its proper divisors (1).

67878661 is an equidigital number, since it uses as much as digits as its factorization.

67878661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 677376, while the sum is 49.

The square root of 67878661 is about 8238.8507086850. The cubic root of 67878661 is about 407.9225891999.

The spelling of 67878661 in words is "sixty-seven million, eight hundred seventy-eight thousand, six hundred sixty-one".