21406773 has 4 divisors (see below), whose sum is σ = 28542368. Its totient is φ = 14271180.

The previous prime is 21406769. The next prime is 21406807. The reversal of 21406773 is 37760412.

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 21406773 - 2² = 21406769 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21406773.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21406703) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3567793 + ... + 3567798.

It is an arithmetic number, because the mean of its divisors is an integer number (7135592).

Almost surely, 2^21406773 is an apocalyptic number.

It is an amenable number.

21406773 is a deficient number, since it is larger than the sum of its proper divisors (7135595).

21406773 is an equidigital number, since it uses as much as digits as its factorization.

21406773 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7135594.

The product of its (nonzero) digits is 7056, while the sum is 30.

The square root of 21406773 is about 4626.7454003868. The cubic root of 21406773 is about 277.6623966257.

The spelling of 21406773 in words is "twenty-one million, four hundred six thousand, seven hundred seventy-three".