21777773 has 2 divisors, whose sum is σ = 21777774. Its totient is φ = 21777772.

The previous prime is 21777751. The next prime is 21777797. The reversal of 21777773 is 37777712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12124324 + 9653449 = 3482^2 + 3107^2 .

It is a cyclic number.

It is not a de Polignac number, because 21777773 - 2⁶ = 21777709 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21777773.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21777713) 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, 10888886 + 10888887.

It is an arithmetic number, because the mean of its divisors is an integer number (10888887).

Almost surely, 2^21777773 is an apocalyptic number.

It is an amenable number.

21777773 is a deficient number, since it is larger than the sum of its proper divisors (1).

21777773 is an equidigital number, since it uses as much as digits as its factorization.

21777773 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 100842, while the sum is 41.

The square root of 21777773 is about 4666.6661547619. Note that the first 3 decimals coincide. The cubic root of 21777773 is about 279.2572705195.

The spelling of 21777773 in words is "twenty-one million, seven hundred seventy-seven thousand, seven hundred seventy-three".