18736861 has 12 divisors (see below), whose sum is σ = 22135680. Its totient is φ = 15721680.

The previous prime is 18736859. The next prime is 18736889. The reversal of 18736861 is 16863781.

It is not a de Polignac number, because 18736861 - 2¹ = 18736859 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 (18736841) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3181 + ... + 6898.

It is an arithmetic number, because the mean of its divisors is an integer number (1844640).

Almost surely, 2^18736861 is an apocalyptic number.

18736861 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18736861 is a deficient number, since it is larger than the sum of its proper divisors (3398819).

18736861 is a wasteful number, since it uses less digits than its factorization.

18736861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10116 (or 10103 counting only the distinct ones).

The product of its digits is 48384, while the sum is 40.

The square root of 18736861 is about 4328.6095920053. The cubic root of 18736861 is about 265.6025732577.

Subtracting from 18736861 its reverse (16863781), we obtain a triangular number (1873080 = T₁₉₃₅).

The spelling of 18736861 in words is "eighteen million, seven hundred thirty-six thousand, eight hundred sixty-one".