18997550 has 48 divisors (see below), whose sum is σ = 41528592. Its totient is φ = 6374400.

The previous prime is 18997543. The next prime is 18997553. The reversal of 18997550 is 5579981.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18997553) 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 23 ways as a sum of consecutive naturals, for example, 5822 + ... + 8478.

It is an arithmetic number, because the mean of its divisors is an integer number (865179).

Almost surely, 2^18997550 is an apocalyptic number.

18997550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18997550 is an abundant number, since it is smaller than the sum of its proper divisors (22531042).

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

18997550 is a wasteful number, since it uses less digits than its factorization.

18997550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2693 (or 2688 counting only the distinct ones).

The product of its (nonzero) digits is 113400, while the sum is 44.

The square root of 18997550 is about 4358.6179002064. The cubic root of 18997550 is about 266.8286949335.

Subtracting from 18997550 its reverse (5579981), we obtain a square (13417569 = 3663²).

It can be divided in two parts, 1899 and 7550, that added together give a palindrome (9449).

The spelling of 18997550 in words is "eighteen million, nine hundred ninety-seven thousand, five hundred fifty".