18965881 has 16 divisors (see below), whose sum is σ = 21434688. Its totient is φ = 16632000.

The previous prime is 18965879. The next prime is 18965887. The reversal of 18965881 is 18856981.

It is not a de Polignac number, because 18965881 - 2¹ = 18965879 is a prime.

It is a super-2 number, since 2×18965881² = 719409284212322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18965887) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47575 + ... + 47971.

It is an arithmetic number, because the mean of its divisors is an integer number (1339668).

Almost surely, 2^18965881 is an apocalyptic number.

18965881 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18965881 is a deficient number, since it is larger than the sum of its proper divisors (2468807).

18965881 is a wasteful number, since it uses less digits than its factorization.

18965881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 552.

The product of its digits is 138240, while the sum is 46.

The square root of 18965881 is about 4354.9834672476. The cubic root of 18965881 is about 266.6803442637.

Subtracting from 18965881 its reverse (18856981), we obtain a square (108900 = 330²).

It can be divided in two parts, 1896 and 5881, that added together give a palindrome (7777).

The spelling of 18965881 in words is "eighteen million, nine hundred sixty-five thousand, eight hundred eighty-one".