18748981 has 4 divisors (see below), whose sum is σ = 18921100. Its totient is φ = 18576864.

The previous prime is 18748967. The next prime is 18749009. The reversal of 18748981 is 18984781.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18984781 = 19 ⋅999199.

It can be written as a sum of positive squares in 2 ways, for example, as 13032100 + 5716881 = 3610^2 + 2391^2 .

It is a cyclic number.

It is not a de Polignac number, because 18748981 - 2⁵ = 18748949 is a prime.

It is a super-2 number, since 2×18748981² = 703048577076722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18748901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85896 + ... + 86113.

It is an arithmetic number, because the mean of its divisors is an integer number (4730275).

Almost surely, 2^18748981 is an apocalyptic number.

It is an amenable number.

18748981 is a deficient number, since it is larger than the sum of its proper divisors (172119).

18748981 is a wasteful number, since it uses less digits than its factorization.

18748981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172118.

The product of its digits is 129024, while the sum is 46.

The square root of 18748981 is about 4330.0093533386. The cubic root of 18748981 is about 265.6598295459.

It can be divided in two parts, 187489 and 81, that multiplied together give a square (15186609 = 3897²).

The spelling of 18748981 in words is "eighteen million, seven hundred forty-eight thousand, nine hundred eighty-one".