21019699 has 2 divisors, whose sum is σ = 21019700. Its totient is φ = 21019698.

The previous prime is 21019657. The next prime is 21019727. The reversal of 21019699 is 99691012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21019699 - 2⁷ = 21019571 is a prime.

It is not a weakly prime, because it can be changed into another prime (21019799) 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, 10509849 + 10509850.

It is an arithmetic number, because the mean of its divisors is an integer number (10509850).

Almost surely, 2^21019699 is an apocalyptic number.

21019699 is a deficient number, since it is larger than the sum of its proper divisors (1).

21019699 is an equidigital number, since it uses as much as digits as its factorization.

21019699 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8748, while the sum is 37.

The square root of 21019699 is about 4584.7245282569. The cubic root of 21019699 is about 275.9786574199.

The spelling of 21019699 in words is "twenty-one million, nineteen thousand, six hundred ninety-nine".