19791855 has 24 divisors (see below), whose sum is σ = 35236032. Its totient is φ = 10269504.

The previous prime is 19791853. The next prime is 19791869. The reversal of 19791855 is 55819791.

It is not a de Polignac number, because 19791855 - 2¹ = 19791853 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 19791855.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19791853) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4279 + ... + 7608.

It is an arithmetic number, because the mean of its divisors is an integer number (1468168).

Almost surely, 2^19791855 is an apocalyptic number.

19791855 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

19791855 is a deficient number, since it is larger than the sum of its proper divisors (15444177).

19791855 is a wasteful number, since it uses less digits than its factorization.

19791855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11935 (or 11932 counting only the distinct ones).

The product of its digits is 113400, while the sum is 45.

The square root of 19791855 is about 4448.8037718020. The cubic root of 19791855 is about 270.4968218723.

The spelling of 19791855 in words is "nineteen million, seven hundred ninety-one thousand, eight hundred fifty-five".