19855435973 has 2 divisors, whose sum is σ = 19855435974. Its totient is φ = 19855435972.

The previous prime is 19855435823. The next prime is 19855436039. The reversal of 19855435973 is 37953455891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18348598849 + 1506837124 = 135457^2 + 38818^2 .

It is a cyclic number.

It is not a de Polignac number, because 19855435973 - 2²⁴ = 19838658757 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19855435573) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9927717986 + 9927717987.

It is an arithmetic number, because the mean of its divisors is an integer number (9927717987).

Almost surely, 2^19855435973 is an apocalyptic number.

It is an amenable number.

19855435973 is a deficient number, since it is larger than the sum of its proper divisors (1).

19855435973 is an equidigital number, since it uses as much as digits as its factorization.

19855435973 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20412000, while the sum is 59.

The spelling of 19855435973 in words is "nineteen billion, eight hundred fifty-five million, four hundred thirty-five thousand, nine hundred seventy-three".