18691428 has 48 divisors (see below), whose sum is σ = 51569280. Its totient is φ = 5155584.

The previous prime is 18691427. The next prime is 18691441. The reversal of 18691428 is 82419681.

It is not an unprimeable number, because it can be changed into a prime (18691423) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1401 + ... + 6272.

It is an arithmetic number, because the mean of its divisors is an integer number (1074360).

Almost surely, 2^18691428 is an apocalyptic number.

It is an amenable number.

18691428 is an abundant number, since it is smaller than the sum of its proper divisors (32877852).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18691428 is a wasteful number, since it uses less digits than its factorization.

18691428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7716 (or 7714 counting only the distinct ones).

The product of its digits is 27648, while the sum is 39.

The square root of 18691428 is about 4323.3584167867. The cubic root of 18691428 is about 265.3877224654.

The spelling of 18691428 in words is "eighteen million, six hundred ninety-one thousand, four hundred twenty-eight".