19799971 has 2 divisors, whose sum is σ = 19799972. Its totient is φ = 19799970.

The previous prime is 19799933. The next prime is 19799977. The reversal of 19799971 is 17999791.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19799971 - 2⁹ = 19799459 is a prime.

It is not a weakly prime, because it can be changed into another prime (19799977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9899985 + 9899986.

It is an arithmetic number, because the mean of its divisors is an integer number (9899986).

Almost surely, 2^19799971 is an apocalyptic number.

19799971 is a deficient number, since it is larger than the sum of its proper divisors (1).

19799971 is an equidigital number, since it uses as much as digits as its factorization.

19799971 is an evil number, because the sum of its binary digits is even.

The product of its digits is 321489, while the sum is 52.

The square root of 19799971 is about 4449.7158336235. The cubic root of 19799971 is about 270.5337908206.

The spelling of 19799971 in words is "nineteen million, seven hundred ninety-nine thousand, nine hundred seventy-one".