18671661 has 32 divisors (see below), whose sum is σ = 30844800. Its totient is φ = 11093760.

The previous prime is 18671659. The next prime is 18671663. The reversal of 18671661 is 16617681.

It is an interprime number because it is at equal distance from previous prime (18671659) and next prime (18671663).

It is not a de Polignac number, because 18671661 - 2¹ = 18671659 is a prime.

It is a super-3 number, since 3×18671661³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18671663) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7651 + ... + 9791.

It is an arithmetic number, because the mean of its divisors is an integer number (963900).

Almost surely, 2^18671661 is an apocalyptic number.

It is an amenable number.

18671661 is a deficient number, since it is larger than the sum of its proper divisors (12173139).

18671661 is a wasteful number, since it uses less digits than its factorization.

18671661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2186 (or 2180 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 18671661 is about 4321.0717420566. The cubic root of 18671661 is about 265.2941364383.

The spelling of 18671661 in words is "eighteen million, six hundred seventy-one thousand, six hundred sixty-one".