21030899 has 2 divisors, whose sum is σ = 21030900. Its totient is φ = 21030898.

The previous prime is 21030881. The next prime is 21030923. The reversal of 21030899 is 99803012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21030899 - 2¹⁶ = 20965363 is a prime.

It is equal to p_1331798 and since 21030899 and 1331798 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 (21030199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10515449 + 10515450.

It is an arithmetic number, because the mean of its divisors is an integer number (10515450).

Almost surely, 2^21030899 is an apocalyptic number.

21030899 is a deficient number, since it is larger than the sum of its proper divisors (1).

21030899 is an equidigital number, since it uses as much as digits as its factorization.

21030899 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 21030899 is about 4585.9458130248. The cubic root of 21030899 is about 276.0276656088.

The spelling of 21030899 in words is "twenty-one million, thirty thousand, eight hundred ninety-nine".