18866661 has 8 divisors (see below), whose sum is σ = 27442464. Its totient is φ = 11434320.

The previous prime is 18866657. The next prime is 18866671. The reversal of 18866661 is 16666881.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18866661 - 2² = 18866657 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18866641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 285826 + ... + 285891.

It is an arithmetic number, because the mean of its divisors is an integer number (3430308).

Almost surely, 2^18866661 is an apocalyptic number.

18866661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18866661 is a deficient number, since it is larger than the sum of its proper divisors (8575803).

18866661 is a wasteful number, since it uses less digits than its factorization.

18866661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 571731.

The product of its digits is 82944, while the sum is 42.

The square root of 18866661 is about 4343.5769821657. The cubic root of 18866661 is about 266.2144848923.

The spelling of 18866661 in words is "eighteen million, eight hundred sixty-six thousand, six hundred sixty-one".