21006419 has 16 divisors (see below), whose sum is σ = 25708800. Its totient is φ = 16762464.

The previous prime is 21006413. The next prime is 21006421. The reversal of 21006419 is 91460012.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21006419 - 2⁸ = 21006163 is a prime.

It is a super-2 number, since 2×21006419² = 882539278407122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21006394 and 21006403.

It is not an unprimeable number, because it can be changed into a prime (21006413) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6509 + ... + 9185.

It is an arithmetic number, because the mean of its divisors is an integer number (1606800).

Almost surely, 2^21006419 is an apocalyptic number.

21006419 is a deficient number, since it is larger than the sum of its proper divisors (4702381).

21006419 is a wasteful number, since it uses less digits than its factorization.

21006419 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2762.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 21006419 is about 4583.2760117628. The cubic root of 21006419 is about 275.9205251463.

The spelling of 21006419 in words is "twenty-one million, six thousand, four hundred nineteen".