21757776673 has 2 divisors, whose sum is σ = 21757776674. Its totient is φ = 21757776672.

The previous prime is 21757776617. The next prime is 21757776683. The reversal of 21757776673 is 37667775712.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19400868369 + 2356908304 = 139287^2 + 48548^2 .

It is a cyclic number.

It is not a de Polignac number, because 21757776673 - 2²¹ = 21755679521 is a prime.

It is not a weakly prime, because it can be changed into another prime (21757776683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10878888336 + 10878888337.

It is an arithmetic number, because the mean of its divisors is an integer number (10878888337).

Almost surely, 2^21757776673 is an apocalyptic number.

It is an amenable number.

21757776673 is a deficient number, since it is larger than the sum of its proper divisors (1).

21757776673 is an equidigital number, since it uses as much as digits as its factorization.

21757776673 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18151560, while the sum is 58.

The spelling of 21757776673 in words is "twenty-one billion, seven hundred fifty-seven million, seven hundred seventy-six thousand, six hundred seventy-three".