20720899 has 2 divisors, whose sum is σ = 20720900. Its totient is φ = 20720898.

The previous prime is 20720893. The next prime is 20720911. The reversal of 20720899 is 99802702.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20720899 - 2⁷ = 20720771 is a prime.

It is not a weakly prime, because it can be changed into another prime (20720893) 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, 10360449 + 10360450.

It is an arithmetic number, because the mean of its divisors is an integer number (10360450).

Almost surely, 2^20720899 is an apocalyptic number.

20720899 is a deficient number, since it is larger than the sum of its proper divisors (1).

20720899 is an equidigital number, since it uses as much as digits as its factorization.

20720899 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18144, while the sum is 37.

The square root of 20720899 is about 4552.0214191060. The cubic root of 20720899 is about 274.6647109299.

The spelling of 20720899 in words is "twenty million, seven hundred twenty thousand, eight hundred ninety-nine".