21076817 has 4 divisors (see below), whose sum is σ = 21086016. Its totient is φ = 21067620.

The previous prime is 21076813. The next prime is 21076841. The reversal of 21076817 is 71867012.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21076817 - 2² = 21076813 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21076813) 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, 1892 + ... + 6762.

It is an arithmetic number, because the mean of its divisors is an integer number (5271504).

Almost surely, 2^21076817 is an apocalyptic number.

It is an amenable number.

21076817 is a deficient number, since it is larger than the sum of its proper divisors (9199).

21076817 is an equidigital number, since it uses as much as digits as its factorization.

21076817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9198.

The product of its (nonzero) digits is 4704, while the sum is 32.

The square root of 21076817 is about 4590.9494660691. The cubic root of 21076817 is about 276.2284087327.

The spelling of 21076817 in words is "twenty-one million, seventy-six thousand, eight hundred seventeen".