68138561 has 2 divisors, whose sum is σ = 68138562. Its totient is φ = 68138560.

The previous prime is 68138509. The next prime is 68138573. The reversal of 68138561 is 16583186.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46840336 + 21298225 = 6844^2 + 4615^2 .

It is a cyclic number.

It is not a de Polignac number, because 68138561 - 2²⁶ = 1029697 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (68131561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34069280 + 34069281.

It is an arithmetic number, because the mean of its divisors is an integer number (34069281).

Almost surely, 2^68138561 is an apocalyptic number.

It is an amenable number.

68138561 is a deficient number, since it is larger than the sum of its proper divisors (1).

68138561 is an equidigital number, since it uses as much as digits as its factorization.

68138561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34560, while the sum is 38.

The square root of 68138561 is about 8254.6084704243. The cubic root of 68138561 is about 408.4425565192.

The spelling of 68138561 in words is "sixty-eight million, one hundred thirty-eight thousand, five hundred sixty-one".