21450019 has 2 divisors, whose sum is σ = 21450020. Its totient is φ = 21450018.

The previous prime is 21449959. The next prime is 21450029. The reversal of 21450019 is 91005412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21450019 - 2¹¹ = 21447971 is a prime.

It is a super-2 number, since 2×21450019² = 920206630200722, which contains 22 as substring.

It is a Chen prime.

It is equal to p_1356601 and since 21450019 and 1356601 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 (21450029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10725009 + 10725010.

It is an arithmetic number, because the mean of its divisors is an integer number (10725010).

Almost surely, 2^21450019 is an apocalyptic number.

21450019 is a deficient number, since it is larger than the sum of its proper divisors (1).

21450019 is an equidigital number, since it uses as much as digits as its factorization.

21450019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 21450019 is about 4631.4165219725. The cubic root of 21450019 is about 277.8492488744.

The spelling of 21450019 in words is "twenty-one million, four hundred fifty thousand, nineteen".