18181622650 has 12 divisors (see below), whose sum is σ = 33817818222. Its totient is φ = 7272649040.

The previous prime is 18181622623. The next prime is 18181622663. The reversal of 18181622650 is 5622618181.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 16116556401 + 2065066249 = 126951^2 + 45443^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 181816177 + ... + 181816276.

Almost surely, 2^18181622650 is an apocalyptic number.

18181622650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18181622650 is a deficient number, since it is larger than the sum of its proper divisors (15636195572).

18181622650 is a wasteful number, since it uses less digits than its factorization.

18181622650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 363632465 (or 363632460 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 40.

The spelling of 18181622650 in words is "eighteen billion, one hundred eighty-one million, six hundred twenty-two thousand, six hundred fifty".