16821139 has 2 divisors, whose sum is σ = 16821140. Its totient is φ = 16821138.

The previous prime is 16821121. The next prime is 16821173. The reversal of 16821139 is 93112861.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 16821139 - 2⁷ = 16821011 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 16821139.

It is not a weakly prime, because it can be changed into another prime (16821839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8410569 + 8410570.

It is an arithmetic number, because the mean of its divisors is an integer number (8410570).

Almost surely, 2^16821139 is an apocalyptic number.

16821139 is a deficient number, since it is larger than the sum of its proper divisors (1).

16821139 is an equidigital number, since it uses as much as digits as its factorization.

16821139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2592, while the sum is 31.

The square root of 16821139 is about 4101.3581896733. The cubic root of 16821139 is about 256.2232092555.

The spelling of 16821139 in words is "sixteen million, eight hundred twenty-one thousand, one hundred thirty-nine".