18691445 has 4 divisors (see below), whose sum is σ = 22429740. Its totient is φ = 14953152.

The previous prime is 18691441. The next prime is 18691487. The reversal of 18691445 is 54419681.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4726276 + 13965169 = 2174^2 + 3737^2 .

It is a cyclic number.

It is not a de Polignac number, because 18691445 - 2² = 18691441 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18691399 and 18691408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18691441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1869140 + ... + 1869149.

It is an arithmetic number, because the mean of its divisors is an integer number (5607435).

Almost surely, 2^18691445 is an apocalyptic number.

It is an amenable number.

18691445 is a deficient number, since it is larger than the sum of its proper divisors (3738295).

18691445 is an equidigital number, since it uses as much as digits as its factorization.

18691445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3738294.

The product of its digits is 34560, while the sum is 38.

The square root of 18691445 is about 4323.3603828504. The cubic root of 18691445 is about 265.3878029227.

The spelling of 18691445 in words is "eighteen million, six hundred ninety-one thousand, four hundred forty-five".