21365019 has 16 divisors (see below), whose sum is σ = 34087200. Its totient is φ = 13147488.

The previous prime is 21365017. The next prime is 21365033. The reversal of 21365019 is 91056312.

21365019 is a `hidden beast` number, since 2 + 1 + 3 + 650 + 1 + 9 = 666.

It is not a de Polignac number, because 21365019 - 2¹ = 21365017 is a prime.

It is a super-2 number, since 2×21365019² = 912928073740722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 21364983 and 21365001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21365017) 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, 30084 + ... + 30785.

It is an arithmetic number, because the mean of its divisors is an integer number (2130450).

Almost surely, 2^21365019 is an apocalyptic number.

21365019 is a deficient number, since it is larger than the sum of its proper divisors (12722181).

21365019 is a wasteful number, since it uses less digits than its factorization.

21365019 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60891 (or 60885 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 21365019 is about 4622.2309548529. The cubic root of 21365019 is about 277.4817519045.

The spelling of 21365019 in words is "twenty-one million, three hundred sixty-five thousand, nineteen".