21049019 has 2 divisors, whose sum is σ = 21049020. Its totient is φ = 21049018.

The previous prime is 21049001. The next prime is 21049027. The reversal of 21049019 is 91094012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21049019 - 2²⁰ = 20000443 is a prime.

It is a super-2 number, since 2×21049019² = 886122401724722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is equal to p_1332890 and since 21049019 and 1332890 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21049219) 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 as a sum of consecutive naturals, namely, 10524509 + 10524510.

It is an arithmetic number, because the mean of its divisors is an integer number (10524510).

Almost surely, 2^21049019 is an apocalyptic number.

21049019 is a deficient number, since it is larger than the sum of its proper divisors (1).

21049019 is an equidigital number, since it uses as much as digits as its factorization.

21049019 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 21049019 is about 4587.9209888576. The cubic root of 21049019 is about 276.1069170242.

The spelling of 21049019 in words is "twenty-one million, forty-nine thousand, nineteen".