18281661 has 16 divisors (see below), whose sum is σ = 25643520. Its totient is φ = 11568960.

The previous prime is 18281651. The next prime is 18281677. The reversal of 18281661 is 16618281.

It is not a de Polignac number, because 18281661 - 2¹³ = 18273469 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18281621) 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, 3075 + ... + 6783.

It is an arithmetic number, because the mean of its divisors is an integer number (1602720).

Almost surely, 2^18281661 is an apocalyptic number.

It is an amenable number.

18281661 is a deficient number, since it is larger than the sum of its proper divisors (7361859).

18281661 is a wasteful number, since it uses less digits than its factorization.

18281661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3796.

The product of its digits is 4608, while the sum is 33.

The square root of 18281661 is about 4275.7059066311. The cubic root of 18281661 is about 263.4340349070.

The spelling of 18281661 in words is "eighteen million, two hundred eighty-one thousand, six hundred sixty-one".