18191572 has 24 divisors (see below), whose sum is σ = 36929984. Its totient is φ = 7679232.

The previous prime is 18191543. The next prime is 18191573. The reversal of 18191572 is 27519181.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18191573) 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, 2973 + ... + 6724.

Almost surely, 2^18191572 is an apocalyptic number.

It is an amenable number.

18191572 is an abundant number, since it is smaller than the sum of its proper divisors (18738412).

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

18191572 is a wasteful number, since it uses less digits than its factorization.

18191572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9775 (or 9773 counting only the distinct ones).

The product of its digits is 5040, while the sum is 34.

The square root of 18191572 is about 4265.1579103241. The cubic root of 18191572 is about 263.0006023879. Note that the first 3 decimals are identical.

The spelling of 18191572 in words is "eighteen million, one hundred ninety-one thousand, five hundred seventy-two".