164780821 has 2 divisors, whose sum is σ = 164780822. Its totient is φ = 164780820.

The previous prime is 164780761. The next prime is 164780827. The reversal of 164780821 is 128087461.

164780821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 147258225 + 17522596 = 12135^2 + 4186^2 .

It is a cyclic number.

It is not a de Polignac number, because 164780821 - 2⁹ = 164780309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (164780827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82390410 + 82390411.

It is an arithmetic number, because the mean of its divisors is an integer number (82390411).

Almost surely, 2^164780821 is an apocalyptic number.

It is an amenable number.

164780821 is a deficient number, since it is larger than the sum of its proper divisors (1).

164780821 is an equidigital number, since it uses as much as digits as its factorization.

164780821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21504, while the sum is 37.

The square root of 164780821 is about 12836.6982125467. The cubic root of 164780821 is about 548.2376881512.

The spelling of 164780821 in words is "one hundred sixty-four million, seven hundred eighty thousand, eight hundred twenty-one".