21606773 has 4 divisors (see below), whose sum is σ = 21629568. Its totient is φ = 21583980.

The previous prime is 21606757. The next prime is 21606787. The reversal of 21606773 is 37760612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21606773 - 2⁴ = 21606757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21606733) 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 in 3 ways as a sum of consecutive naturals, for example, 9911 + ... + 11892.

It is an arithmetic number, because the mean of its divisors is an integer number (5407392).

Almost surely, 2^21606773 is an apocalyptic number.

It is an amenable number.

21606773 is a deficient number, since it is larger than the sum of its proper divisors (22795).

21606773 is an equidigital number, since it uses as much as digits as its factorization.

21606773 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22794.

The product of its (nonzero) digits is 10584, while the sum is 32.

The square root of 21606773 is about 4648.3086171209. The cubic root of 21606773 is about 278.5244357537.

The spelling of 21606773 in words is "twenty-one million, six hundred six thousand, seven hundred seventy-three".