18197121550 has 48 divisors (see below), whose sum is σ = 35143732800. Its totient is φ = 7001769600.

The previous prime is 18197121529. The next prime is 18197121559. The reversal of 18197121550 is 5512179181.

It is a super-2 number, since 2×18197121550² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18197121559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 369796 + ... + 416104.

It is an arithmetic number, because the mean of its divisors is an integer number (732161100).

Almost surely, 2^18197121550 is an apocalyptic number.

18197121550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18197121550 is a deficient number, since it is larger than the sum of its proper divisors (16946611250).

18197121550 is a wasteful number, since it uses less digits than its factorization.

18197121550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46621 (or 46616 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 40.

The spelling of 18197121550 in words is "eighteen billion, one hundred ninety-seven million, one hundred twenty-one thousand, five hundred fifty".