21968773 has 2 divisors, whose sum is σ = 21968774. Its totient is φ = 21968772.

The previous prime is 21968761. The next prime is 21968783. The reversal of 21968773 is 37786912.

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., 20448484 + 1520289 = 4522^2 + 1233^2 .

It is a cyclic number.

It is not a de Polignac number, because 21968773 - 2⁵ = 21968741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21968753) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10984386 + 10984387.

It is an arithmetic number, because the mean of its divisors is an integer number (10984387).

Almost surely, 2^21968773 is an apocalyptic number.

It is an amenable number.

21968773 is a deficient number, since it is larger than the sum of its proper divisors (1).

21968773 is an equidigital number, since it uses as much as digits as its factorization.

21968773 is an evil number, because the sum of its binary digits is even.

The product of its digits is 127008, while the sum is 43.

The square root of 21968773 is about 4687.0857683640. The cubic root of 21968773 is about 280.0712956202.

The spelling of 21968773 in words is "twenty-one million, nine hundred sixty-eight thousand, seven hundred seventy-three".