19904855 has 4 divisors (see below), whose sum is σ = 23885832. Its totient is φ = 15923880.

The previous prime is 19904851. The next prime is 19904869. The reversal of 19904855 is 55840991.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55840991 = 677 ⋅82483.

It is not a de Polignac number, because 19904855 - 2² = 19904851 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19904851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1990481 + ... + 1990490.

It is an arithmetic number, because the mean of its divisors is an integer number (5971458).

Almost surely, 2^19904855 is an apocalyptic number.

19904855 is a deficient number, since it is larger than the sum of its proper divisors (3980977).

19904855 is an equidigital number, since it uses as much as digits as its factorization.

19904855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3980976.

The product of its (nonzero) digits is 64800, while the sum is 41.

The square root of 19904855 is about 4461.4857390784. The cubic root of 19904855 is about 271.0106385079.

The spelling of 19904855 in words is "nineteen million, nine hundred four thousand, eight hundred fifty-five".