18151861 has 16 divisors (see below), whose sum is σ = 22505728. Its totient is φ = 14256000.

The previous prime is 18151849. The next prime is 18151873. The reversal of 18151861 is 16815181.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (18151849) and next prime (18151873).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18151861 is a prime.

It is the 4261-st Hogben number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18152861) by changing a digit.

It is a nontrivial repunit in base 4260.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13081 + ... + 14401.

It is an arithmetic number, because the mean of its divisors is an integer number (1406608).

It is a Poulet number, since it divides 2^18151860-1.

Almost surely, 2^18151861 is an apocalyptic number.

It is an amenable number.

18151861 is a deficient number, since it is larger than the sum of its proper divisors (4353867).

18151861 is a wasteful number, since it uses less digits than its factorization.

18151861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1492.

The product of its digits is 1920, while the sum is 31.

The square root of 18151861 is about 4260.5000880178. The cubic root of 18151861 is about 262.8090919881.

The spelling of 18151861 in words is "eighteen million, one hundred fifty-one thousand, eight hundred sixty-one".