20018513 has 4 divisors (see below), whose sum is σ = 20091060. Its totient is φ = 19945968.

The previous prime is 20018491. The next prime is 20018527. The reversal of 20018513 is 31581002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4870849 + 15147664 = 2207^2 + 3892^2 .

It is a cyclic number.

It is not a de Polignac number, because 20018513 - 2¹⁸ = 19756369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20018543) 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, 35858 + ... + 36411.

It is an arithmetic number, because the mean of its divisors is an integer number (5022765).

Almost surely, 2^20018513 is an apocalyptic number.

It is an amenable number.

20018513 is a deficient number, since it is larger than the sum of its proper divisors (72547).

20018513 is an equidigital number, since it uses as much as digits as its factorization.

20018513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72546.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 20018513 is about 4474.2052925631. The cubic root of 20018513 is about 271.5254891862.

Adding to 20018513 its reverse (31581002), we get a palindrome (51599515).

The spelling of 20018513 in words is "twenty million, eighteen thousand, five hundred thirteen".