20776621 has 2 divisors, whose sum is σ = 20776622. Its totient is φ = 20776620.

The previous prime is 20776619. The next prime is 20776631. The reversal of 20776621 is 12667702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16491721 + 4284900 = 4061^2 + 2070^2 .

It is a cyclic number.

It is not a de Polignac number, because 20776621 - 2¹ = 20776619 is a prime.

Together with 20776619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20776631) 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, 10388310 + 10388311.

It is an arithmetic number, because the mean of its divisors is an integer number (10388311).

Almost surely, 2^20776621 is an apocalyptic number.

It is an amenable number.

20776621 is a deficient number, since it is larger than the sum of its proper divisors (1).

20776621 is an equidigital number, since it uses as much as digits as its factorization.

20776621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7056, while the sum is 31.

The square root of 20776621 is about 4558.1378873395. The cubic root of 20776621 is about 274.9106971740.

The spelling of 20776621 in words is "twenty million, seven hundred seventy-six thousand, six hundred twenty-one".