18501861 has 12 divisors (see below), whose sum is σ = 28696992. Its totient is φ = 10572408.

The previous prime is 18501859. The next prime is 18501871. The reversal of 18501861 is 16810581.

It is a happy number.

It is not a de Polignac number, because 18501861 - 2¹ = 18501859 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18501841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 62785 + ... + 63078.

It is an arithmetic number, because the mean of its divisors is an integer number (2391416).

Almost surely, 2^18501861 is an apocalyptic number.

It is an amenable number.

18501861 is a deficient number, since it is larger than the sum of its proper divisors (10195131).

18501861 is a wasteful number, since it uses less digits than its factorization.

18501861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125880 (or 125873 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 30.

The square root of 18501861 is about 4301.3789649367. The cubic root of 18501861 is about 264.4874917107.

The spelling of 18501861 in words is "eighteen million, five hundred one thousand, eight hundred sixty-one".