18919955 has 4 divisors (see below), whose sum is σ = 22703952. Its totient is φ = 15135960.

The previous prime is 18919949. The next prime is 18919969. The reversal of 18919955 is 55991981.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 18919955 - 2⁴ = 18919939 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1891991 + ... + 1892000.

It is an arithmetic number, because the mean of its divisors is an integer number (5675988).

Almost surely, 2^18919955 is an apocalyptic number.

18919955 is a deficient number, since it is larger than the sum of its proper divisors (3783997).

18919955 is an equidigital number, since it uses as much as digits as its factorization.

18919955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3783996.

The product of its digits is 145800, while the sum is 47.

The square root of 18919955 is about 4349.7074614277. The cubic root of 18919955 is about 266.4649142386.

The spelling of 18919955 in words is "eighteen million, nine hundred nineteen thousand, nine hundred fifty-five".