18991349 has 8 divisors (see below), whose sum is σ = 20547072. Its totient is φ = 17449200.

The previous prime is 18991319. The next prime is 18991361. The reversal of 18991349 is 94319981.

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

It is a cyclic number.

It is not a de Polignac number, because 18991349 - 2²⁰ = 17942773 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18991309) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 377 + ... + 6174.

It is an arithmetic number, because the mean of its divisors is an integer number (2568384).

Almost surely, 2^18991349 is an apocalyptic number.

It is an amenable number.

18991349 is a deficient number, since it is larger than the sum of its proper divisors (1555723).

18991349 is a wasteful number, since it uses less digits than its factorization.

18991349 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6787.

The product of its digits is 69984, while the sum is 44.

The square root of 18991349 is about 4357.9064928013. The cubic root of 18991349 is about 266.7996598773.

The spelling of 18991349 in words is "eighteen million, nine hundred ninety-one thousand, three hundred forty-nine".