18039391 has 8 divisors (see below), whose sum is σ = 18295200. Its totient is φ = 17785440.

The previous prime is 18039389. The next prime is 18039401. The reversal of 18039391 is 19393081.

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 18039391 - 2¹ = 18039389 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 (18039311) 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, 38901 + ... + 39361.

It is an arithmetic number, because the mean of its divisors is an integer number (2286900).

Almost surely, 2^18039391 is an apocalyptic number.

18039391 is a deficient number, since it is larger than the sum of its proper divisors (255809).

18039391 is a wasteful number, since it uses less digits than its factorization.

18039391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 929.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 18039391 is about 4247.2804239890. The cubic root of 18039391 is about 262.2651735145.

The spelling of 18039391 in words is "eighteen million, thirty-nine thousand, three hundred ninety-one".