18994409 has 6 divisors (see below), whose sum is σ = 22095594. Its totient is φ = 16280880.

The previous prime is 18994399. The next prime is 18994421. The reversal of 18994409 is 90449981.

It can be written as a sum of positive squares in only one way, i.e., 12250000 + 6744409 = 3500^2 + 2597^2 .

It is not a de Polignac number, because 18994409 - 2¹² = 18990313 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18994409.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18994499) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 193772 + ... + 193869.

It is an arithmetic number, because the mean of its divisors is an integer number (3682599).

Almost surely, 2^18994409 is an apocalyptic number.

It is an amenable number.

18994409 is a deficient number, since it is larger than the sum of its proper divisors (3101185).

18994409 is an equidigital number, since it uses as much as digits as its factorization.

18994409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 387655 (or 387648 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 44.

The square root of 18994409 is about 4358.2575646696. The cubic root of 18994409 is about 266.8139885613.

The spelling of 18994409 in words is "eighteen million, nine hundred ninety-four thousand, four hundred nine".