18918851 has 16 divisors (see below), whose sum is σ = 23232000. Its totient is φ = 15357384.

The previous prime is 18918829. The next prime is 18918859. The reversal of 18918851 is 15881981.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-18918851 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18918799 and 18918808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18918859) 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 15 ways as a sum of consecutive naturals, for example, 5066 + ... + 7968.

It is an arithmetic number, because the mean of its divisors is an integer number (1452000).

Almost surely, 2^18918851 is an apocalyptic number.

18918851 is a deficient number, since it is larger than the sum of its proper divisors (4313149).

18918851 is an equidigital number, since it uses as much as digits as its factorization.

18918851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2943 (or 2929 counting only the distinct ones).

The product of its digits is 23040, while the sum is 41.

The square root of 18918851 is about 4349.5805544903. The cubic root of 18918851 is about 266.4597312984.

The spelling of 18918851 in words is "eighteen million, nine hundred eighteen thousand, eight hundred fifty-one".