21138219 has 16 divisors (see below), whose sum is σ = 32678400. Its totient is φ = 13479048.

The previous prime is 21138217. The next prime is 21138223. The reversal of 21138219 is 91283112.

It is not a de Polignac number, because 21138219 - 2¹ = 21138217 is a prime.

It is a super-2 number, since 2×21138219² = 893648604983922, which contains 22 as substring.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

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 = 21138192 and 21138201.

It is not an unprimeable number, because it can be changed into a prime (21138217) 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 15 ways as a sum of consecutive naturals, for example, 16399 + ... + 17640.

It is an arithmetic number, because the mean of its divisors is an integer number (2042400).

Almost surely, 2^21138219 is an apocalyptic number.

21138219 is a deficient number, since it is larger than the sum of its proper divisors (11540181).

21138219 is a wasteful number, since it uses less digits than its factorization.

21138219 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34071 (or 34065 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 21138219 is about 4597.6318904410. The cubic root of 21138219 is about 276.4963893113.

The spelling of 21138219 in words is "twenty-one million, one hundred thirty-eight thousand, two hundred nineteen".