20218623 has 4 divisors (see below), whose sum is σ = 26958168. Its totient is φ = 13479080.

The previous prime is 20218621. The next prime is 20218631. The reversal of 20218623 is 32681202.

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

It is a cyclic number.

It is not a de Polignac number, because 20218623 - 2¹ = 20218621 is a prime.

It is a super-2 number, since 2×20218623² = 817585432032258, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20218593 and 20218602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20218621) 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, 3369768 + ... + 3369773.

It is an arithmetic number, because the mean of its divisors is an integer number (6739542).

Almost surely, 2^20218623 is an apocalyptic number.

20218623 is a deficient number, since it is larger than the sum of its proper divisors (6739545).

20218623 is an equidigital number, since it uses as much as digits as its factorization.

20218623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6739544.

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 20218623 is about 4496.5123151171. The cubic root of 20218623 is about 272.4272364149.

Adding to 20218623 its reverse (32681202), we get a palindrome (52899825).

The spelling of 20218623 in words is "twenty million, two hundred eighteen thousand, six hundred twenty-three".