67820561 has 2 divisors, whose sum is σ = 67820562. Its totient is φ = 67820560.

The previous prime is 67820539. The next prime is 67820569. The reversal of 67820561 is 16502876.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52649536 + 15171025 = 7256^2 + 3895^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-67820561 is a prime.

It is not a weakly prime, because it can be changed into another prime (67820569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33910280 + 33910281.

It is an arithmetic number, because the mean of its divisors is an integer number (33910281).

Almost surely, 2^67820561 is an apocalyptic number.

It is an amenable number.

67820561 is a deficient number, since it is larger than the sum of its proper divisors (1).

67820561 is an equidigital number, since it uses as much as digits as its factorization.

67820561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 67820561 is about 8235.3239766265. The cubic root of 67820561 is about 407.8061703465.

The spelling of 67820561 in words is "sixty-seven million, eight hundred twenty thousand, five hundred sixty-one".