19805895 has 12 divisors (see below), whose sum is σ = 34330296. Its totient is φ = 10563120.

The previous prime is 19805893. The next prime is 19805899. The reversal of 19805895 is 59850891.

It is not a de Polignac number, because 19805895 - 2¹ = 19805893 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 440131 = 19805895 / (1 + 9 + 8 + 0 + 5 + 8 + 9 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 19805895.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19805893) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 220021 + ... + 220110.

It is an arithmetic number, because the mean of its divisors is an integer number (2860858).

Almost surely, 2^19805895 is an apocalyptic number.

19805895 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

19805895 is a deficient number, since it is larger than the sum of its proper divisors (14524401).

19805895 is a wasteful number, since it uses less digits than its factorization.

19805895 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440142 (or 440139 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 45.

The square root of 19805895 is about 4450.3814443259. The cubic root of 19805895 is about 270.5607686778.

It can be divided in two parts, 1980 and 5895, that added together give a triangular number (7875 = T₁₂₅).

The spelling of 19805895 in words is "nineteen million, eight hundred five thousand, eight hundred ninety-five".