68778551 has 2 divisors, whose sum is σ = 68778552. Its totient is φ = 68778550.

The previous prime is 68778509. The next prime is 68778557. The reversal of 68778551 is 15587786.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 68778551 - 2¹⁸ = 68516407 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 68778496 and 68778505.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68778557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34389275 + 34389276.

It is an arithmetic number, because the mean of its divisors is an integer number (34389276).

Almost surely, 2^68778551 is an apocalyptic number.

68778551 is a deficient number, since it is larger than the sum of its proper divisors (1).

68778551 is an equidigital number, since it uses as much as digits as its factorization.

68778551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 470400, while the sum is 47.

The square root of 68778551 is about 8293.2834872564. The cubic root of 68778551 is about 409.7173364013.

The spelling of 68778551 in words is "sixty-eight million, seven hundred seventy-eight thousand, five hundred fifty-one".