18948581 has 4 divisors (see below), whose sum is σ = 19044000. Its totient is φ = 18853164.

The previous prime is 18948569. The next prime is 18948623. The reversal of 18948581 is 18584981.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18948581 is a prime.

It is a super-2 number, since 2×18948581² = 718097443827122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18948511) 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, 47411 + ... + 47808.

It is an arithmetic number, because the mean of its divisors is an integer number (4761000).

Almost surely, 2^18948581 is an apocalyptic number.

It is an amenable number.

18948581 is a deficient number, since it is larger than the sum of its proper divisors (95419).

18948581 is an equidigital number, since it uses as much as digits as its factorization.

18948581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95418.

The product of its digits is 92160, while the sum is 44.

The square root of 18948581 is about 4352.9967838261. The cubic root of 18948581 is about 266.5992341649.

The spelling of 18948581 in words is "eighteen million, nine hundred forty-eight thousand, five hundred eighty-one".