18823661 has 4 divisors (see below), whose sum is σ = 19814400. Its totient is φ = 17832924.

The previous prime is 18823657. The next prime is 18823667. The reversal of 18823661 is 16632881.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16632881 = 97 ⋅171473.

It is a cyclic number.

It is not a de Polignac number, because 18823661 - 2² = 18823657 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18823667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 495341 + ... + 495378.

It is an arithmetic number, because the mean of its divisors is an integer number (4953600).

Almost surely, 2^18823661 is an apocalyptic number.

It is an amenable number.

18823661 is a deficient number, since it is larger than the sum of its proper divisors (990739).

18823661 is an equidigital number, since it uses as much as digits as its factorization.

18823661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 990738.

The product of its digits is 13824, while the sum is 35.

The square root of 18823661 is about 4338.6243211414. The cubic root of 18823661 is about 266.0120832320.

The spelling of 18823661 in words is "eighteen million, eight hundred twenty-three thousand, six hundred sixty-one".