18981765 has 48 divisors (see below), whose sum is σ = 37080576. Its totient is φ = 8899200.

The previous prime is 18981751. The next prime is 18981773. The reversal of 18981765 is 56718981.

It is not a de Polignac number, because 18981765 - 2¹³ = 18973573 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 18981765.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 14727 + ... + 15963.

It is an arithmetic number, because the mean of its divisors is an integer number (772512).

Almost surely, 2^18981765 is an apocalyptic number.

18981765 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18981765 is a deficient number, since it is larger than the sum of its proper divisors (18098811).

18981765 is a wasteful number, since it uses less digits than its factorization.

18981765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1290 (or 1287 counting only the distinct ones).

The product of its digits is 120960, while the sum is 45.

The square root of 18981765 is about 4356.8067434762. The cubic root of 18981765 is about 266.7547721024.

It can be divided in two parts, 1898 and 1765, that added together give a palindrome (3663).

The spelling of 18981765 in words is "eighteen million, nine hundred eighty-one thousand, seven hundred sixty-five".