20018623 has 4 divisors (see below), whose sum is σ = 20056168. Its totient is φ = 19981080.

The previous prime is 20018617. The next prime is 20018651. The reversal of 20018623 is 32681002.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32681002 = 2 ⋅16340501.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20018623 is a prime.

It is a super-2 number, since 2×20018623² = 801490533632258, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20018594 and 20018603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20018423) 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, 17961 + ... + 19042.

It is an arithmetic number, because the mean of its divisors is an integer number (5014042).

Almost surely, 2^20018623 is an apocalyptic number.

20018623 is a deficient number, since it is larger than the sum of its proper divisors (37545).

20018623 is an equidigital number, since it uses as much as digits as its factorization.

20018623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37544.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 20018623 is about 4474.2175852321. The cubic root of 20018623 is about 271.5259865217.

Adding to 20018623 its reverse (32681002), we get a palindrome (52699625).

The spelling of 20018623 in words is "twenty million, eighteen thousand, six hundred twenty-three".