67256821 has 2 divisors, whose sum is σ = 67256822. Its totient is φ = 67256820.

The previous prime is 67256801. The next prime is 67256843. The reversal of 67256821 is 12865276.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 56927025 + 10329796 = 7545^2 + 3214^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-67256821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (67256801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33628410 + 33628411.

It is an arithmetic number, because the mean of its divisors is an integer number (33628411).

Almost surely, 2^67256821 is an apocalyptic number.

It is an amenable number.

67256821 is a deficient number, since it is larger than the sum of its proper divisors (1).

67256821 is an equidigital number, since it uses as much as digits as its factorization.

67256821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40320, while the sum is 37.

The square root of 67256821 is about 8201.0256065934. The cubic root of 67256821 is about 406.6730990502.

The spelling of 67256821 in words is "sixty-seven million, two hundred fifty-six thousand, eight hundred twenty-one".