68978551 has 2 divisors, whose sum is σ = 68978552. Its totient is φ = 68978550.

The previous prime is 68978549. The next prime is 68978593. The reversal of 68978551 is 15587986.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 68978551 - 2¹ = 68978549 is a prime.

Together with 68978549, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 68978495 and 68978504.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68978521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34489275 + 34489276.

It is an arithmetic number, because the mean of its divisors is an integer number (34489276).

Almost surely, 2^68978551 is an apocalyptic number.

68978551 is a deficient number, since it is larger than the sum of its proper divisors (1).

68978551 is an equidigital number, since it uses as much as digits as its factorization.

68978551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 604800, while the sum is 49.

The square root of 68978551 is about 8305.3326844865. The cubic root of 68978551 is about 410.1140888132.

The spelling of 68978551 in words is "sixty-eight million, nine hundred seventy-eight thousand, five hundred fifty-one".