20797999 has 2 divisors, whose sum is σ = 20798000. Its totient is φ = 20797998.

The previous prime is 20797981. The next prime is 20798051. The reversal of 20797999 is 99979702.

It is an a-pointer prime, because the next prime (20798051) can be obtained adding 20797999 to its sum of digits (52).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20797999 - 2⁷ = 20797871 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20797949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10398999 + 10399000.

It is an arithmetic number, because the mean of its divisors is an integer number (10399000).

Almost surely, 2^20797999 is an apocalyptic number.

20797999 is a deficient number, since it is larger than the sum of its proper divisors (1).

20797999 is an equidigital number, since it uses as much as digits as its factorization.

20797999 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 642978, while the sum is 52.

The square root of 20797999 is about 4560.4823209832. The cubic root of 20797999 is about 275.0049541807.

The spelling of 20797999 in words is "twenty million, seven hundred ninety-seven thousand, nine hundred ninety-nine".