18900981 has 24 divisors (see below), whose sum is σ = 30214080. Its totient is φ = 11289600.

The previous prime is 18900971. The next prime is 18900983.

18900981 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 18900981 - 2⁵ = 18900949 is a prime.

It is a super-2 number, since 2×18900981² = 714494165524722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18900983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5685 + ... + 8373.

It is an arithmetic number, because the mean of its divisors is an integer number (1258920).

Almost surely, 2^18900981 is an apocalyptic number.

18900981 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18900981 is a deficient number, since it is larger than the sum of its proper divisors (11313099).

18900981 is a wasteful number, since it uses less digits than its factorization.

18900981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2777 (or 2774 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 36.

The square root of 18900981 is about 4347.5258481118. The cubic root of 18900981 is about 266.3758090876.

It can be divided in two parts, 18900 and 981, that added together give a square (19881 = 141²).

The spelling of 18900981 in words is "eighteen million, nine hundred thousand, nine hundred eighty-one".