21704019 has 16 divisors (see below), whose sum is σ = 31974912. Its totient is φ = 13025408.

The previous prime is 21704017. The next prime is 21704027. The reversal of 21704019 is 91040712.

It is a cyclic number.

It is not a de Polignac number, because 21704019 - 2¹ = 21704017 is a prime.

It is a super-2 number, since 2×21704019² = 942128881504722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21704019.

It is not an unprimeable number, because it can be changed into a prime (21704017) 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 15 ways as a sum of consecutive naturals, for example, 8079 + ... + 10424.

It is an arithmetic number, because the mean of its divisors is an integer number (1998432).

Almost surely, 2^21704019 is an apocalyptic number.

21704019 is a deficient number, since it is larger than the sum of its proper divisors (10270893).

21704019 is a wasteful number, since it uses less digits than its factorization.

21704019 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18546.

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 21704019 is about 4658.7572377191. The cubic root of 21704019 is about 278.9416637838.

The spelling of 21704019 in words is "twenty-one million, seven hundred four thousand, nineteen".