21689803 has 2 divisors, whose sum is σ = 21689804. Its totient is φ = 21689802.

The previous prime is 21689797. The next prime is 21689821. The reversal of 21689803 is 30898612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21689803 - 2⁵ = 21689771 is a prime.

It is not a weakly prime, because it can be changed into another prime (21689893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10844901 + 10844902.

It is an arithmetic number, because the mean of its divisors is an integer number (10844902).

Almost surely, 2^21689803 is an apocalyptic number.

21689803 is a deficient number, since it is larger than the sum of its proper divisors (1).

21689803 is an equidigital number, since it uses as much as digits as its factorization.

21689803 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 21689803 is about 4657.2312590207. The cubic root of 21689803 is about 278.8807487864.

The spelling of 21689803 in words is "twenty-one million, six hundred eighty-nine thousand, eight hundred three".