21000599 has 2 divisors, whose sum is σ = 21000600. Its totient is φ = 21000598.

The previous prime is 21000589. The next prime is 21000601. The reversal of 21000599 is 99500012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21000599 - 2⁴ = 21000583 is a prime.

It is a Sophie Germain prime.

Together with 21000601, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000509) 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 as a sum of consecutive naturals, namely, 10500299 + 10500300.

It is an arithmetic number, because the mean of its divisors is an integer number (10500300).

Almost surely, 2^21000599 is an apocalyptic number.

21000599 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000599 is an equidigital number, since it uses as much as digits as its factorization.

21000599 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 810, while the sum is 26.

The square root of 21000599 is about 4582.6410507479. The cubic root of 21000599 is about 275.8950407808.

The spelling of 21000599 in words is "twenty-one million, five hundred ninety-nine", and thus it is an aban number.