18561013 has 8 divisors (see below), whose sum is σ = 19153368. Its totient is φ = 17973504.

The previous prime is 18561001. The next prime is 18561029. The reversal of 18561013 is 31016581.

It can be written as a sum of positive squares in 4 ways, for example, as 777924 + 17783089 = 882^2 + 4217^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18561013 - 2⁵ = 18560981 is a prime.

It is a super-2 number, since 2×18561013² = 689022407172338, 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 (18561083) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7545 + ... + 9697.

It is an arithmetic number, because the mean of its divisors is an integer number (2394171).

Almost surely, 2^18561013 is an apocalyptic number.

It is an amenable number.

18561013 is a deficient number, since it is larger than the sum of its proper divisors (592355).

18561013 is a wasteful number, since it uses less digits than its factorization.

18561013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2423.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 18561013 is about 4308.2494124644. The cubic root of 18561013 is about 264.7690547546.

Adding to 18561013 its reverse (31016581), we get a palindrome (49577594).

The spelling of 18561013 in words is "eighteen million, five hundred sixty-one thousand, thirteen".