21210499 has 2 divisors, whose sum is σ = 21210500. Its totient is φ = 21210498.

The previous prime is 21210491. The next prime is 21210521. The reversal of 21210499 is 99401212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21210499 - 2³ = 21210491 is a prime.

It is not a weakly prime, because it can be changed into another prime (21210491) 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, 10605249 + 10605250.

It is an arithmetic number, because the mean of its divisors is an integer number (10605250).

Almost surely, 2^21210499 is an apocalyptic number.

21210499 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210499 is an equidigital number, since it uses as much as digits as its factorization.

21210499 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 21210499 is about 4605.4857507108. The cubic root of 21210499 is about 276.8111812548.

The spelling of 21210499 in words is "twenty-one million, two hundred ten thousand, four hundred ninety-nine".