18409997 has 8 divisors (see below), whose sum is σ = 19582200. Its totient is φ = 17247744.

The previous prime is 18409987. The next prime is 18410003. The reversal of 18409997 is 79990481.

It can be written as a sum of positive squares in 4 ways, for example, as 3924361 + 14485636 = 1981^2 + 3806^2 .

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 18409997 - 2⁶ = 18409933 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 (18409907) 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, 1529 + ... + 6257.

It is an arithmetic number, because the mean of its divisors is an integer number (2447775).

Almost surely, 2^18409997 is an apocalyptic number.

18409997 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

18409997 is a deficient number, since it is larger than the sum of its proper divisors (1172203).

18409997 is a wasteful number, since it uses less digits than its factorization.

18409997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4975.

The product of its (nonzero) digits is 163296, while the sum is 47.

The square root of 18409997 is about 4290.6872409907. The cubic root of 18409997 is about 264.0490276637.

The spelling of 18409997 in words is "eighteen million, four hundred nine thousand, nine hundred ninety-seven".