19928917 has 2 divisors, whose sum is σ = 19928918. Its totient is φ = 19928916.

The previous prime is 19928863. The next prime is 19928921. The reversal of 19928917 is 71982991.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13608721 + 6320196 = 3689^2 + 2514^2 .

It is a cyclic number.

It is not a de Polignac number, because 19928917 - 2⁷ = 19928789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19928617) 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, 9964458 + 9964459.

It is an arithmetic number, because the mean of its divisors is an integer number (9964459).

Almost surely, 2^19928917 is an apocalyptic number.

It is an amenable number.

19928917 is a deficient number, since it is larger than the sum of its proper divisors (1).

19928917 is an equidigital number, since it uses as much as digits as its factorization.

19928917 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 46.

The square root of 19928917 is about 4464.1815599279. The cubic root of 19928917 is about 271.1197983433.

The spelling of 19928917 in words is "nineteen million, nine hundred twenty-eight thousand, nine hundred seventeen".