21804719 has 2 divisors, whose sum is σ = 21804720. Its totient is φ = 21804718.

The previous prime is 21804701. The next prime is 21804737. The reversal of 21804719 is 91740812.

It is a balanced prime because it is at equal distance from previous prime (21804701) and next prime (21804737).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21804719 is a prime.

It is a super-2 number, since 2×21804719² = 950891541337922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21804779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10902359 + 10902360.

It is an arithmetic number, because the mean of its divisors is an integer number (10902360).

Almost surely, 2^21804719 is an apocalyptic number.

21804719 is a deficient number, since it is larger than the sum of its proper divisors (1).

21804719 is an equidigital number, since it uses as much as digits as its factorization.

21804719 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 32.

The square root of 21804719 is about 4669.5523340038. The cubic root of 21804719 is about 279.3723996008.

The spelling of 21804719 in words is "twenty-one million, eight hundred four thousand, seven hundred nineteen".