21185019 has 24 divisors (see below), whose sum is σ = 32411600. Its totient is φ = 13296960.

The previous prime is 21185011. The next prime is 21185023. The reversal of 21185019 is 91058112.

It is not a de Polignac number, because 21185019 - 2³ = 21185011 is a prime.

It is a super-2 number, since 2×21185019² = 897610060060722, 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 = 21184983 and 21185001.

It is not an unprimeable number, because it can be changed into a prime (21185011) 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 23 ways as a sum of consecutive naturals, for example, 38889 + ... + 39429.

Almost surely, 2^21185019 is an apocalyptic number.

21185019 is a deficient number, since it is larger than the sum of its proper divisors (11226581).

21185019 is a wasteful number, since it uses less digits than its factorization.

21185019 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 795 (or 792 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 27.

The square root of 21185019 is about 4602.7186531440. The cubic root of 21185019 is about 276.7002931661.

The spelling of 21185019 in words is "twenty-one million, one hundred eighty-five thousand, nineteen".