21099773 has 2 divisors, whose sum is σ = 21099774. Its totient is φ = 21099772.

The previous prime is 21099769. The next prime is 21099779. The reversal of 21099773 is 37799012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13410244 + 7689529 = 3662^2 + 2773^2 .

It is a cyclic number.

It is not a de Polignac number, because 21099773 - 2² = 21099769 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21099779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10549886 + 10549887.

It is an arithmetic number, because the mean of its divisors is an integer number (10549887).

Almost surely, 2^21099773 is an apocalyptic number.

It is an amenable number.

21099773 is a deficient number, since it is larger than the sum of its proper divisors (1).

21099773 is an equidigital number, since it uses as much as digits as its factorization.

21099773 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23814, while the sum is 38.

The square root of 21099773 is about 4593.4489221064. The cubic root of 21099773 is about 276.3286578767.

The spelling of 21099773 in words is "twenty-one million, ninety-nine thousand, seven hundred seventy-three".