21120019 has 2 divisors, whose sum is σ = 21120020. Its totient is φ = 21120018.

The previous prime is 21120017. The next prime is 21120041. The reversal of 21120019 is 91002112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21120019 - 2¹ = 21120017 is a prime.

It is a super-2 number, since 2×21120019² = 892110405120722, which contains 22 as substring.

Together with 21120017, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21119984 and 21120011.

It is not a weakly prime, because it can be changed into another prime (21120017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560009 + 10560010.

It is an arithmetic number, because the mean of its divisors is an integer number (10560010).

Almost surely, 2^21120019 is an apocalyptic number.

21120019 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120019 is an equidigital number, since it uses as much as digits as its factorization.

21120019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36, while the sum is 16.

The square root of 21120019 is about 4595.6521844021. The cubic root of 21120019 is about 276.4170120906.

The spelling of 21120019 in words is "twenty-one million, one hundred twenty thousand, nineteen".