19855993 has 2 divisors, whose sum is σ = 19855994. Its totient is φ = 19855992.

The previous prime is 19855961. The next prime is 19855999. The reversal of 19855993 is 39955891.

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., 19784704 + 71289 = 4448^2 + 267^2 .

It is an emirp because it is prime and its reverse (39955891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19855993 - 2⁵ = 19855961 is a prime.

It is not a weakly prime, because it can be changed into another prime (19855999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9927996 + 9927997.

It is an arithmetic number, because the mean of its divisors is an integer number (9927997).

Almost surely, 2^19855993 is an apocalyptic number.

It is an amenable number.

19855993 is a deficient number, since it is larger than the sum of its proper divisors (1).

19855993 is an equidigital number, since it uses as much as digits as its factorization.

19855993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 437400, while the sum is 49.

The square root of 19855993 is about 4456.0063958661. The cubic root of 19855993 is about 270.7886998216.

The spelling of 19855993 in words is "nineteen million, eight hundred fifty-five thousand, nine hundred ninety-three".