21210773 has 2 divisors, whose sum is σ = 21210774. Its totient is φ = 21210772.

The previous prime is 21210769. The next prime is 21210799. The reversal of 21210773 is 37701212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21141604 + 69169 = 4598^2 + 263^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210773 - 2² = 21210769 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21210703) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605386 + 10605387.

It is an arithmetic number, because the mean of its divisors is an integer number (10605387).

Almost surely, 2^21210773 is an apocalyptic number.

It is an amenable number.

21210773 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210773 is an equidigital number, since it uses as much as digits as its factorization.

21210773 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 588, while the sum is 23.

The square root of 21210773 is about 4605.5154977483. The cubic root of 21210773 is about 276.8123732106.

Adding to 21210773 its reverse (37701212), we get a palindrome (58911985).

The spelling of 21210773 in words is "twenty-one million, two hundred ten thousand, seven hundred seventy-three".