20777389 has 2 divisors, whose sum is σ = 20777390. Its totient is φ = 20777388.

The previous prime is 20777371. The next prime is 20777401. The reversal of 20777389 is 98377702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20775364 + 2025 = 4558^2 + 45^2 .

It is a cyclic number.

It is not a de Polignac number, because 20777389 - 2⁷ = 20777261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20777329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10388694 + 10388695.

It is an arithmetic number, because the mean of its divisors is an integer number (10388695).

Almost surely, 2^20777389 is an apocalyptic number.

It is an amenable number.

20777389 is a deficient number, since it is larger than the sum of its proper divisors (1).

20777389 is an equidigital number, since it uses as much as digits as its factorization.

20777389 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 148176, while the sum is 43.

The square root of 20777389 is about 4558.2221314894. Note that the first 3 decimals coincide. The cubic root of 20777389 is about 274.9140844558.

The spelling of 20777389 in words is "twenty million, seven hundred seventy-seven thousand, three hundred eighty-nine".