18681641 has 8 divisors (see below), whose sum is σ = 20412000. Its totient is φ = 16956640.

The previous prime is 18681613. The next prime is 18681643. The reversal of 18681641 is 14618681.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 18681641 - 2⁶ = 18681577 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18681643) 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, 10730 + ... + 12348.

It is an arithmetic number, because the mean of its divisors is an integer number (2551500).

Almost surely, 2^18681641 is an apocalyptic number.

18681641 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18681641 is a deficient number, since it is larger than the sum of its proper divisors (1730359).

18681641 is a wasteful number, since it uses less digits than its factorization.

18681641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2679.

The product of its digits is 9216, while the sum is 35.

The square root of 18681641 is about 4322.2263938854. The cubic root of 18681641 is about 265.3413945782.

The spelling of 18681641 in words is "eighteen million, six hundred eighty-one thousand, six hundred forty-one".