21002099 has 2 divisors, whose sum is σ = 21002100. Its totient is φ = 21002098.

The previous prime is 21002083. The next prime is 21002101. The reversal of 21002099 is 99020012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21002099 - 2⁴ = 21002083 is a prime.

Together with 21002101, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21002039) 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, 10501049 + 10501050.

It is an arithmetic number, because the mean of its divisors is an integer number (10501050).

Almost surely, 2^21002099 is an apocalyptic number.

21002099 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002099 is an equidigital number, since it uses as much as digits as its factorization.

21002099 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 21002099 is about 4582.8047089092. The cubic root of 21002099 is about 275.9016093666.

The spelling of 21002099 in words is "twenty-one million, two thousand, ninety-nine".