677218021 has 2 divisors, whose sum is σ = 677218022. Its totient is φ = 677218020.

The previous prime is 677217997. The next prime is 677218037. The reversal of 677218021 is 120812776.

It is a happy number.

677218021 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., 639837025 + 37380996 = 25295^2 + 6114^2 .

It is a cyclic number.

It is not a de Polignac number, because 677218021 - 2¹³ = 677209829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (677218081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 338609010 + 338609011.

It is an arithmetic number, because the mean of its divisors is an integer number (338609011).

Almost surely, 2^677218021 is an apocalyptic number.

It is an amenable number.

677218021 is a deficient number, since it is larger than the sum of its proper divisors (1).

677218021 is an equidigital number, since it uses as much as digits as its factorization.

677218021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9408, while the sum is 34.

The square root of 677218021 is about 26023.4129391208. The cubic root of 677218021 is about 878.1650906431.

The spelling of 677218021 in words is "six hundred seventy-seven million, two hundred eighteen thousand, twenty-one".