18491919 has 8 divisors (see below), whose sum is σ = 24675840. Its totient is φ = 12317976.

The previous prime is 18491917. The next prime is 18491927. The reversal of 18491919 is 91919481.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18491919 - 2¹ = 18491917 is a prime.

It is a super-2 number, since 2×18491919² = 683902136605122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18491911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5442 + ... + 8160.

It is an arithmetic number, because the mean of its divisors is an integer number (3084480).

Almost surely, 2^18491919 is an apocalyptic number.

18491919 is a deficient number, since it is larger than the sum of its proper divisors (6183921).

18491919 is a wasteful number, since it uses less digits than its factorization.

18491919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4989.

The product of its digits is 23328, while the sum is 42.

The square root of 18491919 is about 4300.2231337455. The cubic root of 18491919 is about 264.4401089856.

The spelling of 18491919 in words is "eighteen million, four hundred ninety-one thousand, nine hundred nineteen".