18022661 has 4 divisors (see below), whose sum is σ = 18053952. Its totient is φ = 17991372.

The previous prime is 18022649. The next prime is 18022673. The reversal of 18022661 is 16622081.

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: 16622081 = 7 ⋅2374583.

It is an interprime number because it is at equal distance from previous prime (18022649) and next prime (18022673).

It is a cyclic number.

It is not a de Polignac number, because 18022661 - 2¹⁰ = 18021637 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18022661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18022681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14765 + ... + 15938.

It is an arithmetic number, because the mean of its divisors is an integer number (4513488).

Almost surely, 2^18022661 is an apocalyptic number.

It is an amenable number.

18022661 is a deficient number, since it is larger than the sum of its proper divisors (31291).

18022661 is an equidigital number, since it uses as much as digits as its factorization.

18022661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31290.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 18022661 is about 4245.3104715674. The cubic root of 18022661 is about 262.1840722280.

The spelling of 18022661 in words is "eighteen million, twenty-two thousand, six hundred sixty-one".